Device and method for manufacturing thread line

ABSTRACT

Production of a yarn, using a spinneret having numerous spinning holes arranged in a straight line(s), and a spinning tube installed below it, spaced from it, and having a filament passage rectangular in cross section with its long side direction agreeing with the direction in which the spinning holes are arranged side by side, wherein gas is injected from the injection holes formed on both the long sides of the filament passage for injecting gas obliquely downward to the filaments, for disposing the numerous filaments in a row and for forming a gas stream flowing downward in the filament passage, characterized in that the speed of the gas stream flowing downward in the filament passage is not less than 60% of the take-up speed of the numerous filaments, or that the gas generated from the numerous filaments is sucked and discharged outside, in the range between the spinneret and the spinning tube. Even if the yarn runs at a high speed, the obtained yarn can have a high elongation.

TECHNICAL FIELD

The present invention relates to a method and apparatus for producing ayarn consisting of numerous filaments, comprising the steps ofdischarging a flowable polymer from numerous spinning holes formed in aspinneret, to form the numerous filaments, letting the formed numerousfilaments pass through a filament passage satisfying specific gas streamconditions of a spinning tube installed below the spinneret, taking upthe numerous filaments coming out of the filament passage, and windingthe numerous filaments.

A typical example of the polymer used in the yarn production method is apolyester polymer (e.g., polyethylene terephthalate). Furthermore, theyarn production method can also be preferably used for producing apartially oriented yarn.

BACKGROUND ART

For producing a yarn, especially a partially oriented yarn (POY) of apolyester or the like, generally an apparatus shown in FIG. 1 is used.In FIG. 1, a spinneret 1 has numerous spinning holes 6. Numerousfilaments F discharged from the spinning holes 6 are cooled andsolidified by means of cooling air 3 a supplied by a cooling means 3.The solidified numerous filaments F are taken up by a godet roller 4, toform a yarn Y. The yarn Y consisting of the numerous filaments F iswound around a bobbin by a winder 5, to produce a yarn package.

To enhance yarn production efficiency, it is generally attempted toraise a yarn production speed. In the case where the apparatus shown inFIG. 1 is used, if the yarn take-up speed of a godet roller 4 is raised,the take-up tension T acting on the filaments F upstream of the godetroller 4 increases. As a result, the elongation of the produced yarn Ydeclines. That is, for example, if a yarn of polyethylene terephthalateis produced at a take-up speed of 3,000 m/min, the elongation of theproduced yarn becomes 135%. If the take-up speed is increased to 4,000m/min, the elongation of the yarn becomes 90%, and if the take-up speedis increased to 5,000 m/min, the elongation of the yarn becomes 65%. Ata higher take-up speed, the elongation of the produced yarn becomeslower.

Furthermore, in the apparatus shown in FIG. 1, a circular spinneret 1shown in FIG. 2 is used. The spinneret 1 has numerous spinning holes 6.The polymer discharged from the numerous spinning holes 6 forms numerousfilaments F. The numerous filaments F run downward. To the runningnumerous filaments F, cooling air 3 a is supplied from one side only.Especially when the take-up speed is high, the volume of the cooling air3 a is also increased. Therefore, the filaments F swing very greatly.Furthermore, since the distances of the respective numerous filaments Ffrom a cooling means 3 are different, the respective filaments F arecooled in different conditions. The yarn Y consisting of the numerousfilaments F produced in this way has filament irregularity.

As described above, it is difficult to produce a yarn at a highertake-up speed for achieving a higher production efficiency with the yarnelongation kept at the same level as achieved at a low take-up speedwithout causing any difference among the filaments constituting the yarn(without causing filament irregularity).

An attempt to overcome the difficulty for obtaining a high elongationyarn at a high speed is described in U.S. Pat. No. 5,824,248. Theoutline of the attempt is shown in FIG. 3. The spinning apparatus shownin FIG. 3 has a cylindrical cooling means 55 and a tube 73 having adiameter smaller than that of the cylindrical cooling means 55 below aspinneret 1. Cooling air 55 a of the cylindrical cooling means 55generates a descending air stream in the tube 73 positioned downstreamof it. It is proposed to impart an air stream in the tube 73 to thenumerous filaments F discharged from the numerous spinning holes 6 ofthe spinneret 1.

JP-A-08-506393 proposes to adjust a flow velocity of an air streamflowing in a tube to a velocity equal to a running speed of the polymer,for decreasing a take-up tension T acting on the filaments. It isdescribed that this constitution allows a yarn to be produced stablyeven if a take-up speed of the yarn is kept high.

However, in these methods, like the apparatus shown in FIG. 1, a polymeris discharged from the numerous spinning holes 6 formed in the circularspinneret 1 shown in FIG. 2, to form numerous filaments F. Therefore,the distances of the respective numerous filaments F from thecylindrical cooling means 55 are different. Furthermore, due to thedifference in diameter between the cylindrical cooling means 55 and thetube 73, the cooling air 55 a becomes different in its state between theoutside and the inside of the numerous filaments. Therefore, the outsiderunning filaments F are different in cooling state from the insiderunning filaments F. The yarn Y consisting of the numerous filaments Fproduced in this way has filament irregularity.

JP-A-2001-262427 proposes to inject a heating fluid from heating fluidinjection holes formed around the spinning holes of the spinneretobliquely downward to the running filaments. It is intended that thefilaments discharged from the spinning holes are kept at a hightemperature and made thinner by means of the heating fluid flow. It isdescribed that with this constitution, even if the spinning speed israised, that is, even if the filament take-up speed is raised, a highelongation yarn can be obtained. Furthermore, it is described that if asuction means is installed downstream of the heating fluid injectionholes, the discharged filaments can be made thinner more positively.

However, in this spinning apparatus, the heating fluid injected from theheating fluid injection holes flows toward the suction means. So, thereis a problem that the heating medium heats the suction means.Furthermore, there is another problem that the heating fluid introducedinto the suction means destabilizes temperature of a gas stream runningin the suction means. The unstable temperature condition affects thefilaments running in the suction means. The yarn produced afterundergoing this condition has filament irregularity.

Moreover, since the heating fluid injection holes are formed directly inthe spinneret, the injected heating fluid does not have an establishedpassage on the discharge face of the spinning holes of the spinneret,and is merely released into the space between the spinneret and thesuction means. For this reason, between the central portion and the endportions of the numerous spinning holes arranged along straight lines, aproblem arises that force of the heating fluid acting on the filamentsbecomes different. The yarn consisting of numerous filaments producedlike this has filament irregularity.

On the other hand, it can happen that a gas is generated from thepolymer flow as just discharged from the spinning holes of thespinneret. The gas contains low polymerization products of the intendedpolymer, i.e., the monomer, oligomer (hereinafter called a volatilesubstance), etc. The volatile substance is deposited on the spinneretface and its vicinity. The deposit causes the filaments to be brokenduring spinning. If a filament is broken, the spinning work must besuspended to correct the trouble, disturbing the continuous operation ofspinning process. Such a gas is generated not only in the case wherepolyethylene terephthalate is spun, but also in the case where anotherpolymer is spun. Especially, thermally decomposable polymers such aspolyamides, polypropylene and aliphatic polyesters (polylactic acid,etc.) generate the gas in a large amount. The deposition of the volatilesubstance caused by the generated gas disturbs the continuous operationof spinning process.

JP-B-50-13924 and JP-A-9-250022 respectively disclose a device forsucking a gas generated below the spinneret. The device sucks the gasfrom lateral sides of the polymer flow (filaments F) as just dischargedthe spinning holes of the spinneret.

However, according to the suction method, in the case where thefilaments F are discharged from the numerous spinning holessubstantially uniformly distributed in the circular spinneret shown inFIG. 2, only the gas existing near the filaments F positioned outsidecan be sufficiently sucked. Therefore, the gas existing near thefilaments positioned inside cannot be sufficiently removed. There occursa state where the running filaments F entrain the gas, to carry it inthe running direction of the filaments F.

Also in the spinning process disclosed in U.S. Pat. No. 5,824,248mentioned above, the gas is generated below the spinneret. However, inthis case, since the cylindrical cooling means 55 keeps the area belowthe spinneret 1 gas-tight, the cooling air 55 a supplied from it carriesthe gas containing the volatile substance toward the tube 73 positioneddownstream and is discharged from the bottom end of the tube 73.Therefore, no gas remains near the spinneret face, and the adhesion ofthe deposit to the spinneret face caused by the gas is hard to occur.So, in such a spinning apparatus, it is not necessary to install thesuction means as described in JP-B-50-13924 or JP-A-09-250022 mentionedabove for decreasing the contamination of the spinneret face.

On the other hand, U.S. Pat. No. 5,824,248 mentioned above proposes thatthe inner diameter of the tube should be 25 mm or more. Therefore, inthis spinning apparatus, since a tube having a large inner diameter isused, even if the volatile substance in the passing gas is deposited onthe inner wall of the tube, it does not affect the filaments running inthe tube.

The object of the invention is to overcome the above-mentioned problemsof the prior art, by providing a method and apparatus for producing ayarn free from irregularity and having a high elongation even if thespeed for taking up the numerous filaments is raised.

DISCLOSURE OF THE INVENTION

The present invention provides a method for producing a yarn consistingof numerous filaments, using:

(a) a spinneret having numerous spinning holes to discharge a flowablepolymer continuously for forming filaments,

(b) a spinning tube having a filament passage through which the numerousfilaments formed by the numerous spinning holes run downward from thespinneret, and installed below and spaced from the spinneret,

(c) an oiling means for applying an oil to the numerous filaments comingout of the spinning tube,

(d) a filament take-up means for taking up the numerous filaments comingfrom the oiling means, and

(e) a winding means for winding the numerous filaments coming from thefilament take-up means, characterized in that

(f) gas injection holes are provided, which inject gas obliquelydownward from outside the numerous filaments entering the filamentpassage of the spinning tube, toward the numerous filaments, while thenumerous filaments are still flowable, to ensure that the numerousfilaments can be disposed along one straight line or one circle withoutoverlapping each other, and further to ensure that, subsequently afterdisposing the numerous filaments, the injected gas can form a gas streamflowing downward together with the numerous filaments in the filamentpassage of the spinning tube, and

(g) the velocity of the gas stream flowing downward together with thenumerous filaments in the filament passage of the spinning tube is notless than 60% of the take-up speed of the numerous filaments taken up bythe filament take-up means.

In the yarn production method of the invention, either of the followingrequirements (g) can be employed instead of the above-mentionedrequirement (g).

A method for producing a yarn, wherein

(g) the following relation is satisfied:La≦Lg/2where Lg is the distance between the spinneret and the position at whichthe numerous filaments are solidified to lose their flowability andreach the take-up speed of the numerous filaments taken up by thefilament take-up means, and La is the distance between the spinneret andthe position at which the acceleration of the numerous filaments becomeslargest.

A method for producing a yarn, wherein

(g) a gas suction device is installed between the spinneret and thespinning tube, to suck the gas existing around the numerous filamentsand to discharge the gas outside.

In the yarn production method of the invention, it is preferred that thenumerous filaments are disposed along one straight line, that the crosssectional form of the filament passage of the spinning tube isrectangular, that the direction of the long sides of the rectangleagrees with the direction of the straight line, and that the followingrelation is satisfied:d×3≦Ex≦d×20where Ex is the length of the short sides of the rectangle, and d is thediameter of the spinning holes.

In the yarn production method of the invention, it is preferred that thenumerous spinning holes are arranged in straight lines, and that thenumber of the straight lines is 3 or less.

In the yarn production method of the invention, it is preferred that thefollowing relation is satisfied:La≦Lg/2where Lg is the distance between the spinneret and the position at whichthe numerous filaments are solidified to lose their flowability andreach the take-up speed of the numerous filaments taken up by thefilament take-up means, and La is the distance between the spinneret andthe position at which the acceleration of the numerous filaments becomeslargest.

In the yarn production method of the invention, it is preferred that avelocity of the gas stream flowing downward together with the numerousfilaments in the filament passage of the spinning tube is higher thanthe running speed of the numerous filaments in the range of the distanceLg between the spinneret and the position at which the running speed ofthe numerous filaments reaches the take-up speed of the numerousfilaments taken up by the filament take-up means.

In the yarn production method of the invention, it is preferred that agas suction and discharge means for sucking and discharging gas existingaround the numerous filaments running from the spinning holes toward thefilament passage is installed between the spinneret and the spinningtube, to ensure that the gas existing around the numerous filaments canbe sucked and discharged.

In the yarn production method of the invention, it is preferred that thenumerous filaments are disposed along one straight line, that the crosssectional form of the filament passage of the spinning tube isrectangular, that the direction of the long sides of the rectangleagrees with the direction of the straight line, and that the followingrelation is satisfiedEx≦10 mmwhere Ex is the length of the short sides of the rectangle.

The apparatus for producing a yarn of the invention is as follows.

An apparatus for producing a yarn consisting of numerous filaments,having:

(a) a spinneret having numerous spinning holes formed to discharge aflowable polymer continuously for forming filaments,

(b) a spinning tube having a filament passage through which the numerousfilaments formed by the numerous spinning holes run downward from thespinneret, and installed below and spaced from the spinneret,

(c) an oiling means for applying an oil to the numerous filaments comingout of the spinning tube,

(d) a filament take-up means for taking up the numerous filaments comingfrom the oiling means, and

(e) a winding means for winding the numerous filaments coming from thefilament take-up means, characterized in that

(f) gas injection holes are provided, which inject gas obliquelydownward from outside the numerous filaments entering the filamentpassage of the spinning tube, toward the numerous filaments, while thenumerous filaments are still flowable, to ensure that the numerousfilaments can be disposed along one straight line or one circle withoutoverlapping each other, and further to ensure that, subsequently afterdisposing the numerous filaments, the injected gas can form an airstream flowing downward together with the numerous filaments in thefilament passage of the spinning tube, and

(g) a means is provided for adjusting the injection conditions of thegas injected from the gas injection holes or adjusting the take-up speedof the numerous filaments taken up by the filament take-up means, toensure that the velocity of the gas stream flowing downward togetherwith the numerous filaments in the filament passage of the spinning tubeis not less than 60% of the take-up speed of the numerous filamentstaken up by the filament take-up means.

In the yarn production apparatus of the invention, either of thefollowing requirements (g) can be employed instead of theabove-mentioned requirement (g).

An apparatus for producing a yarn, wherein

(g) the following relation is satisfied:La≦Lg/2where Lg is the distance between the spinneret and the position at whichthe numerous filaments are solidified to lose their flowability andreach the take-up speed of the numerous filaments taken up by thefilament take-up means, and La is the distance between the spinneret andthe position at which the acceleration of the numerous filaments becomeslargest.

An apparatus for producing a yarn, wherein

(g) a gas suction device is installed between the spinneret and thespinning tube, to suck the gas existing around the numerous filamentsand to discharge the gas outside.

In the yarn production apparatus of the invention, it is preferred thatthe numerous filaments are disposed along one straight line, that thecross sectional form of the filament passage of the spinning tube isrectangular, that the direction of the long sides of the rectangleagrees with the direction of the straight line, and that the followingrelation is satisfied:d×3≦Ex≦d×20where Ex is the length of the short sides of the rectangle, and d is thediameter of the spinning holes.

In the yarn production apparatus of the invention, it is preferred thatthe numerous spinning holes are arranged in straight lines, and that thenumber of the straight lines is 3 or less.

In the yarn production apparatus of the invention, it is preferred thatthe following relation is satisfied:La<Lg/2where Lg is the distance between the spinneret and the position at whichthe numerous filaments are solidified to lose their flowability andreach the take-up speed of the numerous filaments taken up by thefilament take-up means, and La is the distance between the spinneret andthe position at which the acceleration of the numerous filaments becomeslargest.

In the yarn production apparatus of the invention, it is preferred thatthe velocity of the gas stream flowing downward together with thenumerous filaments in the filament passage of the spinning tube ishigher than the running speed of the numerous filaments in the range ofthe distance Lg between the spinneret and the position at which therunning speed of the numerous filaments reaches the take-up speed of thenumerous filaments taken up by the filament take-up means.

In the yarn production apparatus of the invention, it is preferred thata gas suction and discharge means for sucking and discharging gasexisting around the numerous filaments running from the spinning holestoward the filament passage is installed between the spinneret and thespinning tube, to ensure that the gas existing around the numerousfilaments can be sucked and discharged.

In the yarn production apparatus of the invention, it is preferred thatthe numerous filaments are disposed along one straight line, that thecross sectional form of the filament passage of the spinning tube isrectangular, that the direction of the long sides of the rectangleagrees with the direction of the straight line, and that the followingrelation is satisfied:Ex≦10 mmwhere Ex is the length of the short sides of the rectangle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic typical view showing a conventional yarnproduction apparatus.

FIG. 2 is a schematic typical view showing the bottom face of thespinneret used in the apparatus of FIG. 1.

FIG. 3 is a schematic typical view showing another conventional yarnproduction apparatus than the apparatus of FIG. 1.

FIG. 4 is a schematic typical view showing an embodiment of the yarnproduction apparatus of the invention.

FIGS. 5A, 5B and 5D are schematic typical views showing the bottom facesof three typical examples of the spinneret used in the apparatus of FIG.4. FIG. 5C is a projected typical front view showing the spinneret ofFIG. 5B. FIG. 5E is a projected typical front view of the spinneret ofFIG. 5D.

FIG. 6 is a schematic vertical sectional view showing the spinning tubeused in the apparatus of FIG. 4.

FIG. 7 is a schematic X-X cross-sectional view showing the spinning tubeof FIG. 6.

FIG. 8 is a schematic perspective view showing a partial upper portionof the spinning tube of FIG. 4.

FIG. 9 is a schematic vertical sectional view showing another mode ofthe spinning tube of FIG. 4.

FIG. 10 is a schematic vertical sectional view showing a lower portionof a further other mode of the spinning tube of FIG. 4.

FIG. 11 is a partial schematic vertical sectional view showing a mode inwhich a discharge-destined flow suction means is provided below thespinning tube in the apparatus of FIG. 4.

FIG. 12 is a partial schematic vertical sectional view showing a mode inwhich flow regulation sections are installed above the spinning tube inthe apparatus of FIG. 4.

FIG. 13 is a perspective view showing an example of the grate membersinstalled in the flow regulation sections of FIG. 12.

FIG. 14 is a partial schematic perspective view showing a mode in whichan air stream regulation means is installed above the spinning tube inthe apparatus of FIG. 4.

FIG. 15 is a schematic perspective view showing a temperature regulationmeans installed above the spinning tube in the apparatus of FIG. 4.

FIG. 16 is a schematic perspective view showing another mode of thetemperature regulation means of FIG. 15.

FIG. 17 is a partial schematic vertical sectional view showing a mode inwhich a compressed air circulation passage is added to the spinning tubein the apparatus of FIG. 4.

FIG. 18 is a schematic typical view showing another embodiment of theyarn production apparatus of the invention.

FIG. 19 is a schematic vertical sectional view showing a mode of the gassuction device used in the apparatus of FIG. 18.

FIG. 20 is a schematic vertical sectional view showing another mode ofthe gas suction device used in the apparatus of FIG. 18.

FIG. 21 is a schematic vertical sectional view showing a further othermode of the gas suction device used in the apparatus of FIG. 18.

FIG. 22 is a schematic cross sectional view showing the gas suctiondevice used in the apparatus of FIG. 18.

FIG. 23 is a schematic typical view showing a further other embodimentof the yarn production apparatus of the invention.

FIG. 24 is a schematic perspective view showing a mode of the gratemembers of the flow regulation sections of FIG. 23.

FIG. 25 is a schematic perspective view showing the flow regulationsections of FIG. 23.

FIG. 26 is a schematic typical view showing a further other embodimentof the yarn production apparatus of the invention.

FIG. 27 is a graph showing how the speed of the filaments composed of apolymer discharged from the spinneret changes in relation with thedistance from the spinneret in the apparatus of FIG. 4.

FIG. 28 is a schematic perspective view showing the spinning tube andthe oiling means installed in the apparatus of FIG. 4.

FIG. 29 is a schematic perspective typical view showing a further otherembodiment of the yarn production apparatus of the invention.

FIG. 30 is a partial schematic perspective typical view showing afurther other embodiment of the yarn production apparatus of theinvention.

FIG. 31 is a partial schematic perspective typical view showing afurther other embodiment of the yarn production apparatus of theinvention.

FIG. 32 is a schematic typical view for illustrating the method ofmeasuring the running speed of filaments.

FIG. 33 is a graph showing how the speed of the filaments composed of apolymer discharged from the spinneret changed in relation with thedistance from the spinneret in Examples 1 through 4.

FIG. 34 is a graph showing how the speed of the filaments composed of apolymer discharged from the spinneret changed in relation with thedistance from the spinneret in Comparative Examples 1 through 3.

FIG. 35 is a graph showing how the speed of the filaments composed of apolymer discharged from the spinneret changed in relation with thedistance from the spinneret in Examples 1 and 5 and Comparative Example4.

THE BEST MODES FOR CARRYING OUT THE INVENTION

Embodiments of the invention are described below further in reference todrawings.

In the following embodiments, the method and apparatus for producing apolyester yarn, especially a partially oriented yarn (POY) aredescribed.

In FIG. 4, a yarn production apparatus 10 of the invention has aspinneret 12 engaged with a spinning block 11 in a melt-spinning machine(not illustrated) and having numerous spinning holes 13 formed forcontinuously discharging a flowable polymer for forming filaments. Belowthe spinneret 12 and being spaced from the spinneret 12, a spinning tube(ejector) (air applying means) 20 is installed. The spinning tube 20 hasa filament passage 25 (FIG. 6) through which the numerous filaments Fformed by the numerous spinning holes 13 and running downward from thespinneret 12 pass. Downstream of the spinning tube 20, an oiling means17 is installed for applying an oiling agent to the numerous filaments Fcoming from the filament passage 25 of the spinning tube 20. Further, afirst godet roller 14 and a second godet roller 15 constituting afilament take-up means are installed for taking up the numerousfilaments F coming from the oiling means 17. Still further, a windingmeans 16 is installed for winding the numerous filaments F coming fromthe filament take-up means. The numerous filaments F are wound around abobbin 16 a as a yarn Y by the winding means 16, to form a yarn package16 b.

The spinning tube 20 can be moved vertically by means of an elevator 26installed outside. The elevator 26 comprises a vertically extending androtatable column 26 d provided with a ball screw 26 b, a motor 26 c forrotating the column 26 d, and a spinning tube support arm 26 a connectedat one end with the ball screw 26 b, to be able to move vertically alongthe column 26 d with the rotation of the ball screw 26 b, and connectedat the other end with the spinning tube 20. The elevator 26 is actuatedto adjust the distance between the bottom face of the spinneret 12 andthe top face of the spinning tube 20 to a desired value.

FIG. 5A is a bottom face view showing an example of the spinneret 12used in the apparatus of FIG. 4. The spinneret 12A of FIG. 5A hasnumerous spinning holes 13 having a hole diameter of d (mm). Thenumerous spinning holes 13 are arranged along a straight line Z at apitch of P (mm). Six spinning holes 13 are shown in FIG. 5A. In thedrawing, the distance between the center of the rightmost spinning hole13 and the center of the leftmost spinning hole 13 is indicated bysymbol dw.

FIG. 5B is a bottom face view showing another example of the spinneret12 used in the apparatus of FIG. 4. The spinneret 12B of FIG. 5B has thespinning holes 13 of the spinneret 12A of FIG. 5A in two rows, insteadof one row. The spinnerets 13 are arranged along straight lines Z1 andZ2 parallel to each other. The positions of the spinning holes 13 on thestraight line Z1 and the positions of the spinning holes 13 on thestraight line Z2 are shifted from each other in the straight-linedirection. This state is shown in FIG. 5C as projected on the planeincluding the straight-line direction and the direction of the verticalline to the spinneret 12B. This state is necessary to ensure that thenumerous filaments F are disposed along one straight line withoutoverlapping each other in the case where air is injected obliquelydownward from outside the numerous filaments F toward the numerousfilaments in the spinning tube 20 described later. In FIG. 5B, thecenters of the respective spinning holes 13 are positioned on thestraight lines Z1 and Z2 respectively, and the distance between thearrangement of the spinning holes 13 on the straight line Z1 and thearrangement of the spinning holes 13 on the straight line Z2 is thedistance in the direction perpendicular to the straight lines Z1 and Z2,and this distance is indicated by symbol W in FIG. 5B. This distance Wis the longest distance between the arrangement lines of spinnerets,that is, in the case where the spinning holes are arranged in 3 rows,the outermost two straight lines are selected for referring to thedistance W.

FIG. 5D is a bottom face view showing a further other example of thespinneret 12 used in the apparatus of FIG. 4. In the spinneret 12D ofFIG. 5D, the spinning holes 13 are not arranged regularly like straightlines on the surface of the spinneret. The spinning holes 13 arearranged at random. This state is shown in FIG. 5E as projected on theplane including the straight-line direction and the direction of thevertical line to the spinneret 12D. This state is necessary to ensurethat the numerous filaments F are disposed along one straight linewithout overlapping each other in the case where air is injectedobliquely downward from outside the numerous filaments F toward thenumerous filaments in the spinning tube 20 described later. In FIG. 5D,the distance between the centers of the spinning holes 13 of theoutermost positions in the width direction (the direction perpendicularto the longitudinal direction) of the spinneret 12D is indicated bysymbol W. In this case, it is preferred that the following relation issatisfied.W≦10 Exwhere Ex is the length of the short sides 21S of the rectangle as thecross sectional form of the filament passage 25 of the spinning tube 20described later.

As for the arrangement of the numerous spinning holes 13 in thespinneret 12, they can also be arranged like a circle, though such anarrangement is not illustrated in the drawings FIGS. 5A-5E.

In the case where the same number of spinning holes are arranged in thespinneret, if the spinning holes are arranged in plural rows, the lengthof the spinning tube 20 in the straight-line Z direction can beshortened, and the flow rate Ef of the air injected into the spinningtube 20 can be decreased, to allow the reduction of operation cost. Ifthe distance W between the respective rows is too large, the dischargedfilaments F composed of a polymer may be bent greatly, to make theproduced yarn irregular. It is preferred to keep the distance W betweenthe respective rows as small as possible, considering the phenomenonthat the filaments F are swollen at a position immediately below thespinning holes 13.

The structure of the spinning tube 20 used in the apparatus of FIG. 4 isexplained below in reference to FIG. 6.

The spinning tube 20 comprises an air inlet section 22, an air injectionsection 23, a steady flow section 21 and an air discharge section 24 inthis order from the upstream side toward the downstream side. Thespinning tube 20 has a filament passage 25 through which the numerousfilaments F discharged from the spinning holes 13 of the spinneret 12run toward the filament take-up means 14, in the range from the airinlet section 22 to the air discharge section 24.

The air injection section 23 has air injection holes 23 a in the wallfaces of the filament passage 25 on both sides for injecting airobliquely downward from outside the running numerous filaments F towardthe numerous filaments F. The air injection holes 23 a are connectedwith an air supply device 41, and compressed air 41 a is supplied to theair injection holes 23 a. The supplied compressed air 41 a is injectedinto the filament passage 25 from the air injection holes 23 a. Theinjection causes outside air to be sucked from the top opening of thespinning tube 20 into the air inlet section 22 in the filament passage25, to form a suction air flow. The sucked air and the air injected fromthe air injection holes 23 a flow toward the downstream side in thefilament passage 25 and become an airstream with a constant velocity inthe steady flow section 21. The air stream that has passed through thesteady flow section 21 is discharged outside from the air dischargesection 24. The air flow injected from the air injection holes 23 acauses the numerous filaments F entering the filament passage 25 to bedisposed in a straight line without overlapping each other in thedirection perpendicular to the paper surface in FIG. 6, and thefilaments as disposed like this run toward the oiling means 17.

The X-X sectional view of the spinning tube 20 shown in FIG. 6 is shownin FIG. 7. In FIG. 7, the cross sectional form of the filament passage25 is rectangular. The rectangular form is kept in the range from theinlet of the filament passage 25 in the air inlet section 22 to theoutlet of the filament passage 25 in the air discharge section 24.

The direction of the long sides 21L of the rectangle agrees with thedirection in which the spinning holes 13 of the spinneret 12 arearranged side by side. Therefore, the direction of the short sides 21Sof the rectangle is perpendicular to the direction in which the spinningholes 13 of the spinneret 12 are arranged side by side.

The length Ey of the long sides 21L of the rectangle as the crosssectional form of the filament passage 25 is only required to be largerthan the distance dw (mm) between the outermost spinning holes 13 of thespinneret 12A, 12B or 12D shown in FIG. 5A, 5B or 5D. Among the airinlet section 22, the air injection section 23, the steady flow section21 and the air discharge section 24, the sizes of the respectiverectangles may be different, and in this case, it is only required thatthe smallest length of the long sides 21L, 22L, 23L and 24L of therectangles is larger than the distance dw between the outermost spinningholes. However, it is preferred that the sizes of the respectiverectangles are equal among the air inlet section 22, the air injectionsection 23, the steady flow section 21 and the air discharge section 24.

On the other hand, in order that the running numerous filaments F can bestably introduced into the filament passage 25, it is more preferredthat the following relation is satisfied:

Length Ey of the long sides of the rectangle>(Distance dw between theoutermost spinning holes+Pitch P of spinning holes)

Furthermore, in order that the air injected into the filament passage 25from the air injection holes 23 a can act on the numerous filaments Fefficiently without waste, it is more preferred the following relationis satisfied:

Length Ey of the long sides of the rectangle<(Distance dw between theoutermost spinning holes+Pitch P of spinning holes×30)

If the length Ex of the short sides of the rectangle is too small, thefilaments are liable to clog the filament passage 25. It is preferredthat the respective short sides 21S, 22S, 23S and 24S of the air inletsection 22, the air injection section 23, the steady flow section 21 andthe air discharge section 24 satisfy the following relation:

Length Ex of the short sides of the rectangle≦(Diameter d of thespinning holes×3)

Moreover, in the steady flow section 21, if the length Ex of the shortside of the rectangle is too large, the running of the numerousfilaments F is destabilized. So, it is preferred that the followingrelation is satisfied.

Length Ex of the short sides of the rectangle≦(Diameter d of thespinning holes×20)

In the apparatus shown in FIG. 6, the air inlet section 22 has a widenedportion 22 a. If the smallest value 22 w (see FIG. 9) of the short sidesof the rectangle as the cross sectional form of the filament passage 25in the air inlet section 22 and the smallest value 21 w (see FIG. 9) ofthe short sides of the rectangle as the cross sectional form of thefilament passage 25 in the steady flow section 21 are set to bedifferent from each other, the amount of the air sucked from outside inthe air inlet section 22 can be set at a desired value.

In FIG. 6, the air injection section 23 has air injection holes 23 a forinjecting air for the numerous filaments F running in the filamentpassage 25, to form an air stream for ensuring that the numerousfilaments F are disposed in a straight line without overlapping eachother. The air injection holes 23 a have an injection angle of θ againstthe running direction of the numerous filaments F, to ensure that thecompressed air 41 a flows toward the air discharge section 24. It ispreferred that the injection angle θ is 45° or less. If the injectionangle θ s more than 45°, the injected air may flow toward the air inletsection 22, to disturb the running of the numerous filaments F.

For enhancing the efficiency of suction of the numerous filaments F intothe passage 25 and reducing the size of the spinning tube 20, it ispreferred that the injection angle θ be in a range of 5° to 15°.Furthermore, the injection holes 23 a are installed on the long sides ofthe filament passage rectangular in the cross section shown in FIG. 7,but the injection holes 23 a can be slits extending in the full lengthof the long sides 21L of the rectangle or arrangements of pluralcircular holes 32 a as shown as a perspective view in FIG. 8.

As shown in FIG. 9, the spinning tube 20 can also comprises injectionblocks 23 b, 23 c and the like that can be assembled and disassembled.In this constitution, for example, the injection angle θ of theinjection holes, the slit width Ei of the injection holes 23 a (or thediameter of circular holes), and the smallest values 21 w or 22 w of theshort sides of the rectangle as the cross sectional form of the filamentpassage 25 in the air inlet section 22 or the steady flow section 21 canbe easily changed to suit desired operation conditions.

The air inlet section 22 has a widened portion 22 a on the most upstreamside (the inlet of the filament passage 25) as shown in FIG. 6. In thisconstitution, the sucked flow 42 a of outside air formed by thecompressed air 41 a injected from the injection holes 23 a can besmoothly formed into the filament passage 25. The widened portion 22 acan be tapered or formed like a rounded trumpet.

The air discharge section 24 has a widened portion 24 a on the mostdownstream side (the outlet of the filament passage 25) as shown in FIG.6. In this constitution, the compressed air 41 a from the air injectionsection 23 and the sucked flow 42 a join to form a running air stream40, and after it has flowed through the steady flow section 21, itbecomes discharge-destined flow 43 a at the bottom end of the airdischarge section 24, being discharged outward from the filament passage25. The widened portion 24 a can be tapered, but it is preferred thatthe widened portion is curved, since the discharge-destined flow 43 acan be smoothly discharged. Furthermore, as shown in FIG. 9, if thebottom end portion of the widened portion 24 a is extended to have apredetermined length 24N having a constant width 24 w maintained, aneffect of diffusing the discharge-destined flow 43 a can be obtainedwhile the discharge-destined flow 43 a is kept regulated, to furtherstabilize the numerous filaments F. On the other hand, it is alsoallowed that the air discharge section 24 does not have the widenedportion 24 a. That is, the wall faces of the steady flow section 21 canextend straight downward. In this constitution, the structure of thespinning tube 20 can be simplified.

In the case where the discharge-destined flow 43 a should swing thefilaments at or before the oiling means 17 (see FIG. 4) installeddownstream of the spinning tube 20, suction ports 46 can be formed inthe air discharge section 24 of the spinning tube 20 as shown in FIG.10, to positively eliminate the discharge-destined flow 43 a from thesuction ports 46 using a suction blower 45. In this constitution, thedischarge-destined flow 43 a can be prevented from flowing toward thedownstream side of the bottom end of the spinning tube 20.

As shown in FIG. 11, a discharge-destined flow suction means 47connected with a suction blower 45 can also be installed downstream ofthe bottom end of the spinning tube 20 and upstream of the oiling means17, for sucking the discharge-destined flow 43 a. In this case, it ispreferred that the cross sectional form of the passage of thedischarge-destined flow suction means 47 is rectangular like the crosssectional form of the filament passage 25 of the spinning tube 20, andthat suction faces 44 a are formed on the faces parallel to thedirection in which the running numerous filaments F are disposed side byside. It is also allowed that the suction ports 46 are formed in the airdischarge section 24 of the spinning tube 20 as shown in FIG. 10, and inaddition, that the discharge-destined flow suction means 47 is installedas shown in FIG. 11.

In order to regulate the sucked flow 42 a formed by the spinning tube20, as shown in FIG. 12, it is preferred to install flow regulationsections 31 having, for example, honeycomb-like grate members. In thisconstitution, the sucked flow 42 a with a predetermined direction can beformed, and a stable air stream can be given to the running numerousfilaments F.

The flow regulation sections 31 are only required to be such that thegrate members are installed in parallel to the direction in which therunning numerous filaments F are disposed side by side, and if the crosssectional form of the passage in the flow regulation sections 31 isrectangular like the filament passage 25 of the spinning tube 20, an airstream can be caused to act more uniformly on the running numerousfilaments F. Furthermore, one of the grate members can be installed onlyon one side of the long sides of the disposed numerous filaments F, butfor stabilizing the running of numerous filaments F more positively, itis preferred to install the grate members on both sides of the disposednumerous filaments F.

If each of the grate members comprises two grate components 31 x and 31y overlaid on each other as shown in FIG. 13, the size of the formedholes 31 z can be adjusted to allow the flow rate of the sucked flow 42a to be easily controlled. Furthermore, for smoothing the sucked flow 42a, it is preferred that the top end of the air inlet section 22 of thespinning tube 20 and the bottom end of the flow regulation sections 31are joined to be flush with each other without any difference formed ata joint 29 of FIG. 12, to ensure that the passage in the flow regulationsections 31 and the filament passage 25 of the spinning tube 20 can beconnected smoothly.

As shown in FIG. 14, an air stream regulation means 30 having both thefunction of the flow regulation sections 31 shown in FIG. 12 and thefunction of regulating the temperature of the supplied air can also beinstalled upstream of the top end of the spinning tube 20. The airstream regulation means 30 is connected to a temperature-regulated airsupply section 33. The air 32 a adjusted at a desired temperaturesupplied from the temperature-regulated air supply section 33 isregulated by the grate members of the flow regulation sections 31, andis positively supplied to the running numerous filaments F. Since airadjusted at a desired temperature is supplied, the numerous filaments Fexisting before the spinning tube 20 are cooled, insulated or heated,depending on the situation. In this constitution, the temperature of thenumerous filaments F can be controlled at a desired temperature.

The air 32 a can be supplied from both sides of the running numerousfilaments F, but it is preferred that the temperature-regulated air issupplied to the numerous filaments F from one side, while the air usedis sucked from the other side. In this constitution, the air streamformed in the spinning tube 20 can be controlled separately from the airstream formed by the air stream regulation means 30. Furthermore, thevolatile substance generated from the numerous filaments F can also besucked for removal, and the contamination of the spinning tube 20 causedby the volatile substance deposited on the inside of the spinning tube20 can also be prevented.

On the upstream side of the top end of the spinning tube 20, atemperature regulation means 35 can also be installed as shown in FIG.15 for controlling the temperature of the numerous filaments F. Thetemperature regulation means 35 comprises a temperature regulation pipe37 shaped like a block, a rectangular temperature regulation passage 35a formed inside the temperature regulation pipe 37, and heating members36 such as ceramic heaters installed in the long side 37 a direction tooppose the numerous filaments F running in the temperature regulationpassage 35 a. The temperature regulation means 35 is equipped with atemperature controller 38 a and a thermometer 38, for controlling thetemperature of the heating members 36, and as a result, the temperatureof the atmosphere in the temperature regulation passage 35 a can becontrolled. In the case where the temperature regulation means 35 isused, the heating members 36 are installed in the direction in which thenumerous filaments F are disposed side by side in such a manner that thefaces of the long sides 37 a of the temperature control pipe 37 can beflush with the faces of the long sides 21L of the steady flow section 21of the spinning tube 20. The temperature regulation means 35 can also becylindrical in appearance as shown in FIG. 16, if the temperatureregulation passage 35 a of the temperature regulation pipe 37 throughwhich the numerous filaments F pass have a rectangular outlet 39 a.

Both the air stream regulation means 30 shown in FIG. 14 and thetemperature regulation means 35 shown in FIG. 15 can also be usedtogether to control the temperature of the numerous filaments F existingupstream of the top end of the spinning tube 20.

For the flow regulation sections 31 and the air stream regulation means30 shown in FIG. 14, and the temperature regulation means 35 shown inFIG. 15, it is preferred that the top end face of the air streamregulation means 30 or the temperature regulation means 35 and thebottom end face of the spinneret 12 or the spinning block 11 areconnected with each other to achieve air tightness, for preventing thatthe outside air flows through the clearance between such a means and thespinneret 12 for disturbing the air stream in the inside filamentpassage and to prevent that the spinneret 12 is cooled.

As shown in FIG. 17, the air supply device 41 for the spinning tube 20shown in FIG. 6 and the suction ports 46 formed in the air dischargesection 24 shown in FIG. 10 (or the discharge-destined flow suctionmeans 47 shown in FIG. 11) can also be connected with each other, to usethe compressed air 41 a supplied to the spinning tube 20 in circulation.In this case, before the compressed air 41 a is supplied to the spinningtube 20, an air controller 49 for controlling, for example, thetemperature and the flow rate should be installed, and the signal of theair controller 49 should be used to adjust the opening of a valve 41 yof a supply pipe 41 x, for example in the case where the flow rate ofthe compressed air 41 a is insufficient.

As shown in FIG. 17, in the case where the air stream regulation means30 is installed upstream of the top end of the spinning tube 20, the airrecovered from the suction ports 46 of the air discharge section 24 (orthe discharge-destined flow suction means 47 shown in FIG. 11) can befed through a bypass pipe 48 for supply again to the air streamregulation means 30 as supply air 32 a.

A mode in which a gas suction device is installed between the spinneretand the spinning tube is described below.

FIG. 18 shows a spinning apparatus, in which a gas suction device 60 isinstalled immediately below the spinneret 12, and the spinning tube 20spaced from the bottom end of the gas suction device 60 is installedbelow the gas suction device 60. In FIG. 19, the gas suction device 60is installed between the spinneret 12 and the spinning tube 20detachably from the spinning apparatus. The gas suction device 60 sucksthe gas containing the volatile substance generated from the numerousfilaments F composed of a polymer discharged from the spinning holes 13of the spinneret 12.

The gas suction device 60 comprises suction buffers 61 and gas suctionports 62 composed of gas permeable grate members. The gas suction ports62 are installed on both sides of the row of the numerous filaments Fcomposed of a polymer discharged from the spinneret 12, to face thenumerous filaments F in parallel to them. The suction buffers 61 areconnected with a gas suction blower 63 for carrying the gas sucked fromthe gas suction ports 62 to outside the apparatus, through a volatilesubstance collection filter 64. Thus the gas is sucked from the bothsides of the row of the numerous filaments F. In this constitution,swinging of the numerous filaments F due to the suction can be reduced.The volatile substance collection filter 64 removes the volatilesubstance contained in the sucked gas, and the remaining gas isdischarged from the gas suction blower 63 to the atmosphere.

If the gas suction device 60 is positioned with its top face kept asclose to the bottom face of the spinneret 12 as possible, the gas can beeffectively sucked. However, if the top face of the gas suction device60 contacts the bottom face of the spinneret 12, the gas suction devicecan cool the spinneret 12. So, it is preferred that the clearancebetween the bottom face of the spinneret 12 and the top face of the gassuction device 60 (the distance between both in the vertical direction)expressed by SL satisfies a relation of SL≦2 mm.

The gas suction ports 62 are formed in planes parallel to the row of thenumerous filaments F. If the gas suction ports 62 are closer to the rowof the numerous filaments F, the gas suction efficiency is higher.However, if they are too close, the gas flow caused by suction causesthe numerous filaments F to be swung greatly, and it may happen that thenumerous filaments F are fused to each other. If the suction distancefrom the gas suction ports 62 to the row of the numerous filaments F isPL, it is preferred to satisfy a relation of 2 mm≦PL≦20 mm.

It is desirable to use flow regulation members low in gas flowresistance such as honeycomb members as the gas suction ports 62 forregulating the flow of sucked gas.

The amounts of sucked gas can be adjusted to desired flow rates by meansof the suction adjusting valves 65. It is desirable to use flow meters66 provided for measuring both the flow rates, to equalize the flowrates of the gas sucked by both the suction ports 62. In thisconstitution, the numerous filaments F can be prevented from swinging.The flow rate can be controlled easily based on the correlation betweenthe values indicated by a negative pressure gauge 67 and the gasvelocities measured beforehand at the gas suction port 62.

Since the running speed of the numerous filaments F running immediatelybelow the spinneret 12 is small, the moving velocity of the gasgenerated from the numerous filaments F running immediately below thespinneret 12 is also small. So, the gas suction velocity can be verysmall. Though depending on the distance between the gas suction ports 62and the numerous filaments F, it is preferred that the gas suctionvelocity is in a range of 5 m/min to 30 m/min. Since the running speedof the numerous filaments F on the more downstream side is higher, it isdesirable to adjust the gas suction ports 62 for ensuring that thesuction flow rates on the downstream side become higher than those onthe upstream side in the gas suction device 60. In this constitution,the gas accompanying the running numerous filaments F can be efficientlycollected.

If the gas suction device 60 sucks the gas existing around the numerousfilaments F, there occurs a phenomenon that the outside air is suckedfrom the surrounding. In this phenomenon, the incoming outside airlowers the temperature around the spinneret 12, and as a result, thespinnability may be impaired.

To prevent this phenomenon, it is desirable to install a heat insulatingplate 12L below the bottom face of the spinneret 12 as shown in FIG. 20.

As another means, it is desirable to keep the suction buffers 61 of thegas suction device 60 spaced from the spinneret 12 as shown in FIG. 21.This can be achieved if the top faces of the suction buffers 61 are keptin contact with the bottom face of the spinning block 11 directly orindirectly through a packing lip. As a further other means, for example,the clearance between the bottom face of the spinning block 11 and thetop faces of the suction buffers 61 can be perfectly closed by means ofthe packing 11 p. In this constitution, the space between the bottomface of the spinneret 12 and the top face of the gas suction device 60is kept gas-tight.

FIG. 22 is a sectional view of the suction device 60 in the directionperpendicular to the direction vertical to the bottom face of thespinneret 12 (the direction perpendicular to the running direction ofthe numerous filaments F in the case where the numerous spinning holes13 of the spinneret 12 are arranged on one straight line).

In the case where the gas suction device 60 sucks the outside air fromboth the lateral sides 62 a open to the outside air of the gas suctionports 62, it can happen that the gas suction device 60 sucks the gaspositioned around the filaments F running on both lateral sides of thenumerous filaments F more strongly than the gas positioned around thefilaments F running inside among the numerous filaments F. In this case,the produced numerous filaments constituting a yarn become differentfrom each other (irregular) in properties. To avoid this phenomenon, itis desirable to close both the lateral sides open to the outside air ofthe gas suction ports 62 using side plates 68.

For the outside air flowing in from the bottom openings of the gassuction device 60, it is desirable to install flow regulation sections31 each having a honeycomb grate member 88 as shown in FIG. 24, betweenthe bottom face of the gas suction device 60 and the top face of thespinning tube 20, for regulating the inflow direction.

In FIG. 23, the outside air 81 a incoming from suction spaces 80 formsan ascending stream against the running direction of the numerousfilaments F. Because of the ascending stream, the gas otherwise destinedto flow down accompanying the running numerous filaments F is turnedtoward the gas suction device 60, and collected by the gas suctiondevice 60. As a result, the inflow of the gas generated near thespinneret 12 into the spinning tube 20 installed downstream of the gassuction device can be prevented.

If the flow regulation sections 31 each having the suction space 80 isinstalled between the bottom end of the gas suction device 60 and thetop end of the spinning tube 20, the sucked flow 42 a caused by thespinning tube 20 is also regulated in the downstream portion in the flowregulation sections 31. In this constitution, the sucked flow 42 adirected as desired is allowed to flow into the filament passage 25 ofthe spinning tube 20. Thus, a stable air stream with a small volatilematter content flows into the filament passage 25 of the spinning tube20.

It is preferred that the flow regulation sections 31 are provided withgrate members 88 arranged with their longitudinal direction kept inparallel with the direction in which the running numerous filaments Fare disposed side by side. The cross sectional form of the filamentpassage in the flow regulation sections 31 can be rectangular like thecross sectional form of the filament passage 25 in the spinning tube 20.In this constitution, the air stream can be caused to more uniformly acton the running numerous filaments F.

It is preferred that the suction spaces 80 of the flow regulationsections 31 are provided on both sides of the disposal of the numerousfilaments F, to further stabilize the running of the numerous filamentsF.

It is only required that the grate members 88 installed in the flowregulation sections 31 are installed to ensure that the air streams areregulated in the direction perpendicular to the direction in which thenumerous filaments F are disposed side by side, in planes perpendicularor inclined to the disposal faces of the numerous filaments F (forexample, the disposal faces of the numerous filaments F formed by therow of spinning holes indicated by the straight line Z in FIG. 5A). Theinclination angle can also change from the top ends to the bottom endsof the grate members 88.

FIG. 24 is a perspective view showing either of the grate members 88used in the flow regulation sections 31 and also the thickness 88 t ofthe grate member 88 in the flow regulation direction. If the thickness88 t in the flow regulation direction is larger, the flow regulationeffect is higher. It is preferred that the grate member 88 is formed tohave a thickness 88 t of 5 mm or more.

The flow regulation sections 31 can also be connected with a blower 33as shown in FIG. 25. The blower 33 positively supplies air to the flowregulation sections 31 of the suction spaces 80, to assist the flow ofthe outside air 81 a flowing toward the suction device 60 and the flowof the sucked flow 42 a flowing toward the spinning tube 20. Dependingon the kind, condition or the like of the polymer constituting therunning filaments, an inert gas such as nitrogen can also be introduced.Hot air or cold air can also be introduced to control the temperature ofthe air acting on the numerous filaments F.

In the production of a yarn, it can happen that a filament is broken. Anexample of how to deal with the situation is described below inreference to FIG. 26. In FIG. 26, in order to monitor the runningpassage of the yarn Y, a filament break sensor 96 is installed betweenthe second godet roller 15 and the winding means 16. When a filament isbroken, the filament break sensor 96 detects it and issues a filamentbreak detection signal. On the other hand, a sucker 95 is installedbetween the spinning tube 20 and the oiling means 17, to face therunning passage of the yarn Y consisting of numerous filaments F. Thesucker 95 is connected with a waste yarn blower 94. If the waste yarnblower 94 is actuated based on a filament break detection signal, thesucker 95 sucks the yarn Y.

Even if a filament is broken, the numerous filaments F continuouslyformed by the spinning holes 13 of the spinneret 12 keep running on theupstream side of the position where the breaking has occurred. Thenumerous filaments F continuously running from the spinneret 12 aresucked and taken up by the waste yarn blower 94 and the sucker 95respectively actuated based the filament break detection signal issuedby the filament break sensor 96 when the sensor has detected thebreaking. Then, the yarn taken up by the sucker 95 is discharged fromthe sucker 95 and accommodated in a waste yarn container 97. In thisconstitution, the winding of the yarn around the first godet roller 14and the second godet roller 15 is prevented. It is preferred that thesucker 95 is installed in such a manner that it opens toward the airdischarge section 24 of the spinning tube 20 and can move horizontallyin the direction in which the numerous filaments F are disposed side byside (the long side direction of the filament passage 25 of the spinningtube 20).

Next, the yarn production method of the invention is described below inreference to FIGS. 4 and 6.

The air supply device 41 injects the compressed air 41 a obliquelydownward into the filament passage 25 of the spinning tube 20 from theinjection holes 23 a. As a result, the air stream 40 running downward inthe filament passage 25 is formed. The spinning tube 20 is installedbelow the spinneret 12 in the vertical direction in such a manner thatthe numerous filaments F composed of a polymer discharged as a row(s)from the numerous spinning holes 13 of the spinneret run straightdownward in the vertical direction through the filament passage 25 ofthe spinning tube 20.

With this arrangement, when the running numerous filaments F havearrived at the inlet of the filament passage 25, the sucked flow 42 aformed in the air inflow section 22 allows the filaments F to be easilyintroduced into the filament passage 25, and further allows thefilaments F to easily pass through the filament passage 25. If theelevator 26 is actuated to lower the spinning tube 20, the filaments Frun stably and can easily pass through the filament passage 25.

A flowable polymer is discharged from the numerous spinning holes 13arranged in a row(s) in the spinneret 12 provided in the spinning block11. The discharged polymer forms numerous filaments F disposed inaccordance with the arranged spinning holes 13. The formed numerousfilaments F are introduced into the inlet of the filament passage 25,and are discharged from the outlet of the filament passage 25. Thepolymer constituting the numerous filaments F loses its flowability andis solidified while it passes through the filament passage 25 of thespinning tube 20. Subsequently, while being sucked by a suction gun (notillustrated), the filaments F discharged from the filament passage 25are fed along the oiling means 17, the first godet roller 14 and thesecond godet roller 15 sequentially, finally being wound by the winder16. Thus, the initial work in the production of yarn Y is completed. Inthe case where the spinning tube 20 used has the suction ports 46 shownin FIG. 10, the operation of the suction blower 45 connected with thesuction ports 46 is suspended till the yarn installation work up to thewinder 16 is completed, and after the yarn installation work has beencompleted, the suction blower 45 is actuated.

Thereafter, the polymer is continuously discharged from the spinningholes 13 of the spinneret 12, to form numerous filaments F. From theinjection holes 23 a formed in the spinning tube 20 toward the filamentpassage 25, air streams are injected obliquely downward toward theformed numerous filaments F on both sides of the numerous filaments F.Receiving the air streams, the numerous filaments F are disposed in onerow without overlapping each other.

Subsequently, the disposed numerous filaments F run downward in thefilament passage 25 with the disposal maintained. On the other hand, theair streams injected from the injection holes 23 a obliquely downwardinto the filament passage 25 for contribution to the maintenance of thedisposal of the numerous filaments F form a downward running air stream40 in the filament passage 25. In the filament passage 25, the downwardrunning numerous filaments F and the downward running air stream 40coexist. The coexistence of the running numerous filaments F and therunning air stream 40 in the filament passage 25 allows that thenumerous filaments F composed of a polymer discharged from the spinningholes 13 are stably drawn and made thinner. As a result, a highelongation yarn Y having little irregularity among the filaments can beproduced at a high speed.

According to the yarn production process, the numerous filaments Fcomposed of a polymer discharged from the spinning holes 13, not yetsolidified, are introduced into the filament passage 25 of the spinningtube 20, and are drawn and made thinner there. Therefore, unlike anonwoven fabric obtained by cooling and solidifying the numerousfilaments composed of a polymer discharged from the spinning holes anddrawing them with an air stream, a high elongation yarn having littleirregularity among the filaments can be produced.

In this yarn production process, since the injection velocity Vs of thecompressed air 41 a from the injection holes 23 is set at a value higherthan the take-up speed Vw of the yarn Y by the first godet roller 14,the velocity of the air running together with the numerous filaments Fis kept at higher than the running speed of the numerous filaments F atleast in part of the filament passage 25 of the spinning tube 20. Inthis state, the drawing force by the air stream flowing downward in thefilament passage 25 acts on the numerous filaments F.

In this yarn production process, to generate a more preferred drawingforce, it is preferred that the running velocity Ve of the running airstream 40 flowing in the steady flow section 21 is kept at not less thana velocity of 60% of the yarn take-up speed Vw.

In the case where the running velocity Ve of the running air stream 40is too high, the running state of the yarn Y near the oiling means 17positioned below the spinning tube 20 may be adversely affected. One ofthe unwanted effects is filament breaking. To prevent such an accident,it is preferred that the running velocity Ve of the running air stream40 is not more than a velocity of 120% of the yarn take-up speed Vw.

The speed Vf of the filaments F composed of a polymer discharged at aninitial speed of Vo from the spinning holes 13 becomes gradually higherwith the increase of distance from the spinneret 12 in the verticaldirection, and it reaches the yarn take-up speed Vw at a certain point.

This relation is shown in FIG. 27. In the graph of FIG. 27, the distancefrom the bottom face of the spinneret 12 in the vertical direction ischosen as the abscissa, and the speed of the filaments F at eachdistance from the bottom face of the spinneret 12 in the verticaldirection is chosen as the ordinate. The speed of the filaments Fchanges as shown by curve A in the graph of FIG. 27. In this case, ifthe distance from the bottom face of the spinneret 12 to the point wherethe speed of the filaments F reaches the yarn take-up speed Vw is Lg,and the distance from the bottom face of the spinneret 12 to the pointwhere the gradient of the curve A becomes largest, i.e., the point wherethe acceleration of filaments F becomes largest, is La, then it ispreferred that a relation of La≦Lg/2 is satisfied. This relation can berealized if the position of the spinning tube 20 to the spinneret 12,the polymer discharge condition from the spinneret 13, the condition ofrunning air stream 40 and the yarn take-up condition are adjusted. Inthe case where the relation of La≦Lg/2 is satisfied, the filaments F canbe made thinner in the upstream region in the filament passage 25. Thisconstitution facilitates the production of a non-oriented yarn Y, i.e.,a high elongation yarn Y.

In the case where the flow regulation sections 31 are installed upstreamof the spinning tube 20 as shown in FIG. 12, the outside air flowingfrom outside into the air inlet section 22 is regulated in flow. In thisconstitution, regulated sucked flow 42 a is formed, and in this state,the sucked flow 42 a can be given to the numerous filaments F running asa row in the direction to cross them. This state exhibits an effect ofuniformly cooling the numerous filaments F. Thus, a yarn Y having littleyarn irregularity can be easily produced.

In the case where the air stream regulation means 30 is installedupstream of the spinning tube 20 as shown in FIG. 14, the atmospheretemperature upstream of the spinning tube 20 can be positivelycontrolled. As shown in FIG. 15, in the case where the temperatureregulation means 35 contained in the temperature regulation pipe 37 isinstalled upstream of the spinning tube 20, the atmosphere in thetemperature regulation passage 35 a through which the numerous filamentsF run can be controlled by radiation heat. This allows the temperatureof the numerous filaments F entering the spinning tube 20 to becontrolled at a desired temperature. This temperature controlfacilitates the production of a yarn Y having desired physicalproperties.

It is preferred that the temperature of the filaments F entering thefilament passage 25 of the spinning tube 20 is 160° C. or higher. A morepreferred temperature is 200° C. or higher. If the temperature of thefilaments F is controlled to such a temperature, the injection flow rateEf of the air injected into the filament passage 25 from the air supplydevice 41 can be decreased to lower the production cost of the yarn Y.

In the case where a filament is broken while the yarn Y is produced, thefilament break sensor 96 detects the filament breaking as shown in FIG.26, and the drive of the drive system ranging from the first godetroller 14 to the winder 16 is stopped. At the same time, the waste yarnblower 94 is actuated, and the waste yarn sucker 95 sucks the filamentscoming from the filament passage 25 as waste filaments F1 while beingreciprocated in the direction in which the numerous filaments F aredisposed side by side (horizontal direction). It is preferred that whilethe filament breaking situation is dealt with like this, the injectionflow rate Ef of the compressed air 41 a into the spinning tube 20 isdecreased more or less compared with the normal flow rate.

As shown in FIG. 29, in the case where there are plural yarn productionlines, if the respective rotation axes J1, J2 and J3 of the first godetrollers 14, the second godet rollers 15 and the winding means 16 arekept in parallel with the direction in which the spinnerets 12 and thespinning tubes 20 are arranged side by side, it can be prevented thatthe yarns Y introduced along the first godet rollers 14 are twisted.This allows the yarns Y to be stably taken up.

When the numerous filaments F are oiled, the numerous filaments F can bebundled as one yarn, but instead, as shown in FIG. 28, an oiling meansconsisting of a long oil supply roller 17 a and an oil coating member 17b for applying an oil to the oil supply roller 17 a can also be used forapplying an oil to each of the filaments.

As shown in FIG. 30, the spinneret installed in the spinning block 11can also have plural spinning hole groups 13 a, each consisting ofplural spinning holes 13, arranged in one direction. As shown in FIG.31, instead of using one spinneret to be installed in the spinning block11, plural spinnerets 12 arranged in one direction, each having pluralspinning holes 13 arranged in the same one direction, can also be used.

In this case, the plural yarns YY can pass through one spinning tube 20,and further along the roller 17 a of one oiling means.

In this case, in the relation between the passage width Eyy in thelongitudinal direction, of the filament passage 25 of this spinning tube20 and the passage width Ey for one spinneret 12 described before (forone yarn), Eyy corresponds to (Ey)×(number of yarns).

According to the yarn production method of the invention, the propertiesof the yarn obtained at a production speed of 3,000 m/min or 4,000 m/minby a conventional method can be realized even at a speed of 5,000 m/minor more. The production speed can also be 6,000 min/min to 10,000 m/mineven in the case where it is intended to obtain a yarn with similarproperties.

Even in a process in which the yarn Y is heated by the first godetroller 14 and drawn between the first godet roller 14 and the secondgodet roller 15 with the speed of the second godet roller 15 kept higherthan the speed of the first godet roller, a similar effect can beobtained.

The yarn production method of the invention satisfies both the qualityand productivity of the obtained yarn in good balance, compared with theyarn production methods of the prior art. Therefore, the yarn productionmethod of the invention can also be used, for example, for producing avery thin yarn with a filament fineness of 0.5 dtex or less difficult inthe control of yarn quality, and also for producing a monofilament.

Another embodiment of the yarn production method of the invention isdescribed below in reference to FIGS. 6, 18 and 19.

The gas suction blower 63 is operated to produce a state in which thegas suction device 60 can suck the gas in the filament passage in thegas suction device 60. On the other hand, the air supply device 41 isoperated to inject the compressed air 41 a into the filament passage 25of the spinning tube 20 from the two injection holes 23 a opened to faceeach other in the filament passage 25, and the air streams injected fromboth the injection holes 23 a collide with each other in the filamentpassage 25, to form a air stream 40 running downward in the filamentpassage 25.

The spinning tube 20 is positioned below the spinneret 12 in thevertical direction, to ensure that the numerous filaments F composed ofa polymer discharged as a row from the spinning holes 13 of thespinneret 12 can run straight downward in the vertical direction, topass through the filament passage 25 of the spinning tube 20.

With this arrangement, when the running numerous filaments F reach theinlet of the filament passage 25, the sucked flow 42 a formed in the airinlet section 22 allows the filaments F to be easily introduced into thefilament passage 25, and facilitates further passage of the filaments Fthrough the filament passage 25. If the elevator 26 is actuated to movethe spinning tube 20 further downward from the spinneret 12, thefilaments F are progressively cooled and solidified, to facilitate theirpassage through the filament passage 25, and at the same time, the gasnear the spinneret 12 generated from the filaments F is sucked into thefilament passage 25 of the spinning tube 20 and discharged outside inthe time zone before start of normal operation (before yarn threading).So, the contamination in the spinning tube 20 by the gas containing thevolatile substance can be avoided. Furthermore, the running of thefilaments F can be stabilized to allow easy passage through the filamentpassage 25.

The gas suction device 60 can also be connected at the top of thespinning tube 20, to ensure that it can be lowered or lifted togetherwith the spinning tube 20. On the other hand, if the gas suction device60 is separate from the spinning tube 20 and installed on the under faceof the spinning block 11 or the spinneret 12, the clearance of thesuction spaces 80 (FIG. 23) can be easily adjusted at a desired distanceby lifting or lowering the spinning tube 20.

Then, a polymer is discharged from the spinning holes 13 arranged in arow in the spinneret 12 installed in the spinning block 11, to formnumerous filaments F. The formed numerous filaments F pass through thefilament passage 25 of the gas suction device 60 and the spinning tube20. The running filaments F are solidified while they pass through thefilament passage 25 of the spinning tube 20. Subsequently, thesolidified filaments F are sucked by a suction gun (not illustrated),and guided along the oiling means 17, the first godet roller 14 and thesecond godet roller 15 sequentially, being finally wound by the winder16. Thus, the initial work in the production of the yarn Y is completed.

Thereafter, the polymer is discharged continuously from the spinneret12, to form numerous filaments F, and the formed numerous filaments Frun downward in the filament passage 25 of the gas suction device 60 andthe spinning tube 20 with their disposal maintained. During this time,the gas suction device 60 sucks the gas generated from the filaments F.In spite of the suction, the compressed air 41 a injected from theinjection holes 23 a acts on the numerous filaments F running throughthe filament passage 25 of the spinning tube 20, and the numerousfilaments F are aligned along a straight line without overlapping eachother. The numerous filaments F running in the filament passage 25 arecooled and solidified while they pass through the filament passage 25.The cooled and solidified numerous filaments F are bundled and oiled bythe oiling means 17. The oiled numerous filaments F are guided as theyarn Y along the first godet roller 14 and the second godet roller 15,being wound around a bobbin by the winder 16. Thus, the yarn Y isproduced as a yarn package.

This yarn production method satisfies both yarn quality and yarnproductivity in good balance compared with the yarn production processesof the prior art. The yarn production process can also be used forproducing a yarn consisting of numerous filaments composed of any ofvarious polymers such as polypropylene and polylactic acid. This yarnproduction process can be used for producing a very thin yarn with afilament fineness of 0.5 dtex or less, or difficult in the control ofyarn quality, and also for producing a thick yarn such as amonofilament.

A first group of Examples and Comparative Examples:

As examples of the yarn production method of the invention, yarnproduction methods using the yarn production apparatus shown in FIG. 4are described below, and as comparative examples, yarn productionmethods using the apparatus shown in FIG. 1 are described. Theproduction conditions used in the examples and comparative examples areshown in the following respective tables.

The spinning tube 20 used in Examples 1 through 13 is shown in FIG. 6.The cross sectional view of the spinning tube 20 and its filamentpassage 25 is shown in FIG. 7. The cross sectional form of the filamentpassage 25 is rectangular. The spinning tube 20 had the air inletsection 22, the air injection section 23, the steady flow section 21 andthe air discharge section 24, to name from the top end to the bottomend. The air inlet section 22 had a widened portion 22 a, and the airdischarge section 24 had a widened portion 24 a. The length Ex of theshort sides 21S in the cross section of the filament passage 25 in thesteady flow section 21 was 2 mm, and the length Ey of the long sides 21Lwas 100 mm. The injection holes 23 a open on the wall faces of thefilament passage 25 respectively had a form of a slit extending over thefull length of the long sides 21L of the filament passage 25. The slitwidth Ei (see FIG. 9) of the slits was 0.4 mm.

It is difficult to directly measure the injection velocity Vs (m/min) ofthe compressed air 41 a injected from the injection holes 23 a of theair injection section 23. Therefore, the value obtained by calculationfrom the injection flow rate Ef (m3/min) of the compressed air 41 asupplied from the blower of the air supply device 41, the crosssectional area of the passage of each injection hole 23 a (Ey×Ei) andthe supply pressure of the compressed air 41 a was employed as theinjection velocity Vs (m/min).

The running air stream velocity Ve (m/min) of the running air stream 40flowing in the steady flow section 21 was obtained from the followingformula based on the differential pressure Po between the respectivepressures obtained from the pressure pipe P1 installed in the wall ofthe steady flow section 21 and the pressure pipe P2 installed in thedownstream region of the air discharge section 24.Ve=(2˜Po/p) ^(1/2)where p is the density of air.

The filament speed Vf (m/min) of the filaments F running between thespinneret 12 and the first godet roller 14 was measured using themeasuring instrument shown in FIG. 32. In FIG. 32, a laser Doppler yarnvelocimeter 50 consisted of a measuring head 51 and a controller 52. Themeasuring head 51 was moved in the running direction of the filaments F,and the filament speed Vf (m/min) of the filaments F running between thespinneret 12 and the first godet roller 14 was measured at every 100 mmposition from the spinneret 12. To measure the filament speed of thefilaments F running through the filament passage 25 in the spinning tube20, the spinning tube 20 was partially opened at a portion correspondingto one short side 21 b of the filament passage 25 so that the laser beamcould reach the inside of the filament passage 25 from the measuringhead 51 when the yarn speed was measured. In the case where the openingaffects the air stream of the filament passage 25, the opening should begiven up, and a small hole for allowing the transmission of the laserbeam for measurement should be formed in the spinning tube 20 at aportion corresponding to one short side 21S of the filament passage 25.As another method, a portion of the spinning tube 20 corresponding toone short side 21S of the filament passage 25 should be made of amaterial capable of transmitting the laser beam for measurement, toallow measurement through the portion.

In FIG. 4, L1 (mm) indicates the distance from the bottom face of thespinneret 12 to the top face of the spinning tube 20, and defines thespinning tube position. L2 (mm) indicates the overall length of thespinning tube 20, and defines the spinning tube length. L3 (mm)indicates the distance from the bottom face of the spinneret 12 to theoiling means 17, and defines the oiling position. L4 (mm) indicates thedistance from the bottom face of the spinneret 12 to the first godetroller 14, and defines the take-up position. Vw (m/min) indicates theyarn Y take-up speed by the first godet roller 14. In FIG. 6, Es (mm)indicates the distance from the top face of the spinning tube 20 to theinjection holes 23 a of the air injection section 23 (the center of theopen faces of the injection holes 23a in the vertical direction on thewall faces of the filament passage 25), and defines the slit position.

In the spinneret 12, the distance between the respectively adjacentspinning holes 13 is expressed as the spinning hole pitch P (mm), andthe hole diameter of the spinning holes 13 on the bottom face of thespinneret 12 is expressed as the spinning hole diameter d (mm) . Thecenter distance between the two spinning holes most apart from eachother among the plural spinning holes 13 is expressed as distance dw(mm) between the outermost spinning holes.

EXAMPLES 1, 2, 3 and 4

The apparatus shown in FIG. 4 was used to produce polyester yarns Y eachconsisting of 36 filaments F with a filament fineness D of 135 dtexunder the conditions shown in Table 1. The spinneret 12 used had all thespinning holes 13, i.e., 36 spinning holes 13 arranged on a straightline Z as shown in FIG. 5A. The spinning hole pitch P was 2.5 mm and thespinning hole diameter d was 0.3 mm. The distance dw between theoutermost spinning holes was 90.3 mm. In Examples 1, 2, 3 and 4, thesame conditions were employed except that the spinning tube position L1was changed. The yarn production conditions and the properties of theobtained yarns are shown together in Table 1 given later.

In every example, the swing of the 36 filaments F running upstream anddownstream of the spinning tube 20 was small, and a good spinning statecould be observed. It was confirmed that the 36 filaments F maintainedtheir disposal obtained immediately after they had been discharged fromthe spinneret 12, in the range from the upstream side of the spinningtube 20 to the outlet of the spinning tube 20, and passed through thespinning tube 20 without being converged (without contacting eachother).

The results of yarn quality evaluation of the yarn Y wound by thewinding means 16 are shown in Table 1. The yarn properties in Example 1were 141% in elongation E, 2.4 g/dtex in strength T and 0.95 in yarnirregularity U%. Those in Example 2 were 128% in elongation E, 2.6g/dtex in strength and 0.93 in yarn irregularity U%. Those in Example 3were 104% in elongation E, 2.8 g/dtex in strength T and 1.00 in yarnirregularity U%. Those in Example 4 were 86% in elongation E, 3.0 g/dtexin strength T and 1.13 in yarn irregularity U%. There was a tendencythat when the spinning tube 20 was farther away from the spinneret 12,the elongation E of the obtained yarn Y was smaller while the yarnirregularity U% became larger.

The filament velocity Vf of the running filaments F was measured atevery 100 mm position from the spinneret 12, and the results are shownin FIG. 33. The distance from the spinneret 12 to the point at which thesolidified filaments F reached the take-up speed Vw was identified asthe take-up speed reaching point Lg, and the distance from the spinneret12 to the middle point between the two points of the largest gradientsin the curve formed by connecting the measuring points was identified asthe acceleration point. The results of these points in the respectiveexamples are shown in Table 2 given later.

From FIG. 33, it can be seen that the position of the acceleration pointLa (acceleration points La1 to La4) shifted toward the downstream sideas the value of the spinning tube position L1 became larger. It also canbe seen that the position of each acceleration point La was on theupstream side of the one half of the distance to the correspondingreaching point Lg (reaching points Lg1 to Lg4). In Examples 1 through 4,the respective acceleration points La were 28%, 39%, 45% and 50% of thereaching points Lg. From the results, it was found that if the relationof acceleration point La<reaching point Lg/2 is satisfied and the ratioof the acceleration point La to the reaching point Lg is lower, then theelongation E of the produced yarn Y becomes higher.

The temperature Ti(0° C.) of the filaments F at right above the airinlet section 22 of the spinning tube 20 was measured using anon-contact type thermometer in each example. The results are shown inTable 2. The temperatures Ti in the respective examples were 215° C. inExample 1, 203° C. in Example 2, 184° C. in Example 3 and 158° C. inExample 4. The results mean that if the value of the spinning tubeposition L1 is smaller, the filaments with a higher temperature enterthe spinning tube 20.

While the filaments F are kept at a high temperature, the filaments Fencounter the compressed air 41A injected obliquely downward toward therunning direction of the filaments F from the injection holes 23 a, andthereafter, together with the running air stream 40 running downward inthe filament passage 25, the filaments run downward in the filamentpassage 25. The coexistence of the filaments F and the running airstream 40 allows the produced yarn Y to have a higher elongation. Theyarn Y obtained like this can have an elongation of not less than 1.5times the elongation of the yarn obtained in Comparative Example 1described later.

In the relation between the spinning tube range Le (mm) in which thespinning tube 20 exists (the range from the bottom face of the spinneret12 to L1 or L1+L2) and the running air stream velocity vV, as shown inTable 2, the respective acceleration points La are within the spinningtube range Le in Examples 1 through 4, and the values VL of the filamentspeed Vf at the acceleration points La are smaller than the values ofthe running air stream velocity Ve. This means that at least partiallyin the spinning tube 20, the drawing force of the running air stream 40acted on the filaments F.

COMPARATIVE EXAMPLES 1, 2 and 3

The apparatus shown in FIG. 1 was used to produce polyester yarns Y eachconsisting of 36 filaments F with a filament fineness D of 135 dtexunder the conditions shown in Table 3. In the respective comparativeexamples, the spinneret 1 shown in FIG. 2 was used. The spinneret 1 had36 spinning holes 6 so arranged within a circle having a diameter dd of72 mm that the filaments discharged from the holes should not contacteach other. The cooling means 3 shown in FIG. 1 supplied cooling air 3 ato the downward running filaments F composed of a polymer dischargedfrom the spinning holes 6 of the spinneret 1, in the directionperpendicular to the vertical direction. The filament cooling length L22in the cooling means was 1,000 mm, and the cooling air velocity Vc1 ofthe cooling air 3 a was 30 m/min. The cooling air 3 a was blown from thecooling air blow face of the cooling means 3 and crossed the runningfilaments F, then being sent substantially in the same direction as theblow direction and discharged out of the cooling means 3. Therefore,there was no air stream that ran in the running direction of thefilaments F and dominated the running filaments F.

In FIG. 1, L11 (mm) indicates the distance from the bottom face of thespinneret 1 to the top face of the cooling means 3, and defines thecooling means position. Comparative Examples 1, 2 and 3 employed thesame conditions except that the yarn take-up speed Vw was changed. Theyarn production conditions and the properties of the obtained yarns inthese comparative examples are shown together in Table 3 given later.

In every comparative example, the swing of the running 35 filamentsupstream and downstream of the cooling means 3 was small. However, itwas confirmed that the cooling air 3 a crossing the filaments F in thedirection substantially perpendicular to the running direction of thefilaments F bent the running filaments F. The bending degree wasdifferent from filament to filament depending on the respective runningpositions resulting from the positions of the arranged spinning holes 6.

The results of yarn quality evaluation of the yarns Y wound by thewinding means 5 are shown in Table 3. The yarn properties in ComparativeExample 1 were 65% in elongation E, 3.1 g/dtex in strength T and 1.24 inyarn irregularity U%. Those in Comparative Example 2 were 98% inelongation E, 2.9 g/dtex in strength T and 1.13 in yarn irregularity U%.Those in Comparative Example 3 were 119% in elongation E, 2.7 g/dtex instrength T and 1.05 in yarn irregularity U%. It was confirmed that whenthe yarn take-up speed Vw was higher, the elongation E of the producedyarn was smaller.

In comparison with Examples 1 through 4, the examples could produce highstrength yarns even at a yarn take-up speed Vw of 5,000 m/min.Especially Example 1 could produce a yarn with an elongation higher thanthat of Comparative Example 3 in which the take-up speed Vw was 3,500m/min.

The filament speed Vf of the running filaments F was measured at every100 mm position from the spinneret 1, and the results are shown in FIG.34. As in Example 1, the reaching points Lg and the acceleration pointsLa are shown in Table 4 given later.

FIG. 34 shows that the increase of take-up speed Vw changed both theposition of the reaching point Lg (reaching points Lg1x to Lg3x) and theposition of the acceleration point (acceleration points La1x to La3x)toward the downstream side. However, the position of every accelerationpoint La was on the downstream side of one half of the distance to theposition of the corresponding reaching point Lg. That is, thecomparative examples showed a relation of acceleration point La>reachingpoint Lg/2 irrespective of the take-up speed Vw.

EXAMPLE 5 AND COMPARATIVE EXAMPLE 4

In Example 5 and Comparative Example 4, the apparatus shown in FIG. 4was used to produce polyester yarns each consisting of 36 filaments Fwith a filament fineness D of 135 dtex as described for Example 1,except that the injection flow rate Ef, the injection velocity Vs andthe running air stream velocity Ve were changed as shown in Table 5given later. The yarn production conditions and the properties of theobtained yarns in Example 5 and Comparative Example 4 are shown in Table5 given later.

In Example 5, the swing of the running 36 filaments F in the positionsupstream and downstream of the spinning tube 20 was small, and a goodspinning state was observed. It was confirmed that the 36 filaments Fmaintained the disposal of filaments F as achieved immediately afterhaving been discharged from the spinneret 12, in the range from theupstream side of the spinning tube 20 to the outlet of the spinning tube20, and that the filaments F passed through the spinning tube 20 withoutbeing converged (without contacting each other). On the other hand, incomparative Example 4, probably because the drawing force of the runningair stream 40 acting on the filaments F was insufficient due to thedecrease of injection flow rate in the spinning tube 20, the disposal ofthe filaments F was disturbed, and it was confirmed that it happenedespecially in the upstream region of the spinning tube 20 and that thefilaments F ran unstably.

The results of yarn quality evaluation of the yarns Y wound by thewinding means 16 are shown in Table 5. The yarn properties in Example 1were 141% in elongation E, 2.4 g/dtex in strength T and 0.95 in yarnirregularity U% at an injection velocity Vs of 6,000 m/min and a runningair stream velocity Ve of 4,250 m/min. On the contrary, those in Example5 were 112% in elongation E, 3.2 g/dtex in strength T and 1.01 in yarnirregularity U% at an injection velocity Vs of 4,900 m/min and a runningair stream velocity Ve of 3,240 m/min. Further, on the contrary, thosein Comparative Example 4 were 84% in elongation E, 3.5 g/dtex instrength T and 1.34 in yarn irregularity U% at an injection velocity Vsof 3,400 m/min and a running air stream velocity Ve of 1,980 m/min.

From these data, it can be seen that in the case where the injectionvelocity Vs and the running air stream velocity Ve are large, a yarnwith a high elongation and small yarn irregularity can be obtained.

It can also be seen that if the injection velocity Vs is higher than thetake-up speed Vw, the amount sucked into the spinning tube 20 isstabilized, allowing a high quality yarn with a high elongation to beobtained.

On the other hand, it can be seen that if the injection velocity Vs islower than the take-up speed, the amount sucked in the spinning tube 20decreases, destabilizing the running of the filament F, hence causingyarn irregularity.

From these results and the results obtained in Examples 2 through 4, itcan be seen that for producing a yarn with a high elongation, keepingthe running air stream velocity Ve at not less than 60% of the take-upspeed Vw is a desirable condition.

The filament speed Vf of the running filaments F at every 100 mmposition from the spinneret was measured, and the results are shown inFIG. 35. As in Example 1, the reaching points Lg and the accelerationpoints La of Example 5 and Comparative Example 4 are shown in Table 6given later.

In FIG. 35, in the case of Example 5, the position of the accelerationpoint La (acceleration point La5) was on the upstream side of one halfof the distance to the position of the reaching point Lg (reaching pointLg5), but in the case of Comparative Example 4, the position of theacceleration point La (acceleration point La4x) was on the downstreamside of one half of the distance to the position of the reaching pointLg (reaching point Lg4x). The results show that unless an air streamhaving an adequate injection velocity Vs and running air stream velocityVe satisfying the relation of the acceleration point La<reaching pointLg/2 is given to the filaments F, a good quality yarn with a highelongation and small yarn irregularity cannot be obtained. As can beseen from Table 6, since the acceleration point La4x was positionedoutside the spinning tube range Le, the running air stream velocity Vedid not effectively act on the filaments F in Comparative Example 4.

EXAMPLES 6 and 7

As shown in Table 7 given later, in Example 6, a polyester yarnconsisting of 36 filaments F with a filament fineness D of 135 dtex wasproduced as described for Example 1, except that the steady flow sectionof the spinning tube 20 was extended to change the spinning tube lengthL2. On the other hand, in Example 7, a polyester yarn consisting of 36filaments F with a filament fineness D of 135 dtex was produced asdescribed for Example 6, except that the injection flow rate Ef and theinjection velocity Vs were adjusted to ensure that the running airstream velocity Ve became virtually equal to that of Example 1 (6,200m/min). The yarn production conditions and the properties of theobtained yarns in these examples are shown together in Table 7 givenlater.

In each example, the swing of the running 36 filaments F in thepositions upstream and downstream of the spinning tube 20 was small, anda good spinning state was observed. It was confirmed that the 36filaments F maintained the disposal of the filaments F as achievedimmediately after having been discharged from the spinneret 12, in therange from the upstream side of the spinning tube 20 to the outlet ofthe spinning tube 20, and that the filaments F passed through thespinning tube 20 without being converged (without contacting eachother).

The results of yarn quality evaluation of the yarns Y wound by thewinding means 16 are shown in Table 7.

The yarn properties of Example 6 were 128% in elongation E, 2.7 g/dtexin strength T and 0.80 in yarn irregularity U% at a running air streamvelocity Ve of 3,680 m/min. Compared with Example 1, the value of yarnirregularity U% was improved. However, though the injection flow rate Efwas equivalent to that of Example 1, it is considered that the pressureresistance caused by the longer steady flow section 21 lowered therunning air stream velocity Ve and also decreased the sucked flow 42 aof the spinning tube 20, to lower the total flow rate of the running airstream 40, thus lowering the running air stream velocity Ve and loweringthe elongation of the obtained yarn.

The yarn properties of Example 7 were 140% in elongation E, 2.4 g/dtexin strength T and 0.82 in yarn irregularity U% at a running air streamvelocity Ve of 4,200 m/min. Compared with Example 1, the elongation Ewas equivalent and the yarn irregularity U% was better. These resultssuggest that a longer spinning tube length L2 can inhibit thedisturbance of the filaments F running in the spinning tube 20, and thata running air stream velocity Ve equivalent to or higher than thetake-up speed Vw is a factor capable of greatly improving the elongationof the yarn. These effects can also be obtained by adjusting the lengthof the bottom end section 24N of the spinning tube 20 of FIG. 9.

EXAMPLES 8, 9 and 10

The spinneret 12 used in Example 8 had numerous spinning holes 13arranged in two straight lines Z1 and Z2 as shown in FIG. 5B. The lengthEy of the long sides 21L in the cross section of the steady flow section21 of the spinning tube 20 was changed to one half of the Ey value ofExample 1. Furthermore, the same yarn production apparatus as used inExample 1 was used except that the injection flow rate Ef and theinjection velocity Vs were adjusted to achieve a running air streamvelocity Ve equivalent to that of Example 1. Polyester yarns eachconsisting of 36 filaments F with a filament fineness D of 135 dtex wereproduced.

In Examples 9 and 10, polyester yarns each consisting of 36 filaments Fwith a filament fineness D of 135 dtex were produced as described forExample 8, except that the injection angle θ of the injection holes 23 ain the spinning tube 20 was changed as shown in Table 8 given later. Theyarn production conditions and the properties of the obtained yarns inthese examples are shown together in Table 8 given later.

In each example, the swing of the running 36 filaments F in thepositions upstream and downstream of the spinning tube 20 was small, anda good spinning state was observed. It was confirmed that the 36filaments F maintained the disposal of the filaments F as achievedimmediately after having been discharged from the spinneret 12, in therange from the upstream side of the spinning tube 20 to the outlet ofthe spinning tube 20, and that the filaments F passed through thespinning tube 20 without being converged (without contacting eachother).

A yarn was produced under the same conditions as in Example 8, exceptthat the spinneret used had the spinning holes 13 arranged in straightlines Z1 and Z2 to overlap each other on the projection drawing of thespinneret, in an attempt to evaluate the yarn similarly. However, inthis case, a phenomenon occurred, in which the filaments F entering thespinning tube 20 fused each other in the upstream region of the spinningtube 20. Since filament breaking and fluffing occurred in the yarn, theyarn was not taken up for evaluation.

The results of yarn quality evaluation of the yarns Y wound by thewinding means 16 are shown in Table 8. The yarn properties of Example 8were 140% in elongation E, 2.4 g/dtex in strength T and 0.98 in yarnirregularity U%. It was found that a yarn with the same quality as thatof Example 1 was obtained. It was confirmed that even in the case wherethe spinneret 12 has spinning holes 13 arranged in two rows, if thespinning holes 13 are positioned to avoid overlapping in the directionperpendicular to the respective straight lines Z1 and Z2, the intendedyarn could be produced without any problem.

If a spinneret having the spinnerets 13 arranged in plural rows isemployed, the length Ey of the long sides of the filament passage 25 ofthe spinning tube 20 can be shortened. In the case where the spinningholes are arranged in two rows, the length Ey becomes about one half ofthe length needed when they are arranged in one row, if the number offilaments F and the filament fineness D are identical. In this case, theinjection flow rate Ef can be decreased to reduce the production costneeded for compressed air consumption.

In Examples 9 and 10 where the injection angle θ was changed, therunning air stream velocity Ve increased when the injection angle θ wasmade sharper, compared with that in Example 8. It is considered that ifthe injection angle θ is smaller, the sucked flow 42 a entering from theinlet of the filament passage 25 of the spinning tube 20 increases toincrease the flow rate of the running air stream 40.

The properties of the wound yarns were evaluated. Those of Example 9were 143% in elongation E, 2.4 g/dtex in strength T and 0.91 in yarnirregularity U% at a running air stream velocity Ve of 4,780 m/min.Those of Example 10 were 145% in elongation E, 2.3 g/dtex in strength Tand 0.88 in yarn irregularity U% at a running air stream velocity Ve of5,230 m/min. That is, it was confirmed that if the injection angle θ issmaller, a good quality yarn with an elongation equivalent or higherthan that of Example 9 could be obtained.

EXAMPLE 11

A polyester yarn consisting of 36 filaments F with a filament fineness Dof 135 dtex was produced as described for Example 1 under the conditionsshown in Table 9 given later, except that an apparatus as shown in FIG.12 was used, in which flow regulation sections 31 having air regulationplates were installed upstream of the spinning tube 20. The airregulating boards were honeycomb grates installed on both sides of thefilaments F at a position immediately above the air inlet section 22 ofthe spinning tube 20. The size of each flow regulation section 31 was 60mm in length Lc and 10 mm in thickness Lt. The yarn productionconditions and the properties of the obtained yarn of Example 11 areshown together in Table 9 given later.

In Example 11, the swing of the running 36 filaments F in the positionsupstream and downstream of the spinning tube 20 was small, and a goodspinning state was observed. It was confirmed that the 36 filaments Fmaintained the disposal of the filaments F as achieved immediately afterhaving been discharged from the spinneret 12, in the range from theupstream side of the spinning tube 20 to the outlet of the spinning tube20, and that the filaments F passed through the spinning tube 20 withoutbeing converged (without contacting each other).

The yarn properties of the wound yarn Y were evaluated and found to be143% in elongation E, 2.4 g/dtex in strength T and 0.85 in yarnirregularity U%. Compared with Example 1, since the air regulationplates regulated the sucked flow 42 a, it could be visually confirmedthat the swing of the filaments F in the position upstream of thespinning tube 20 was smaller than that in Example 1, and that because ofit, the yarn irregularity could be further improved.

EXAMPLES 12 and 13

Polyester yarns each consisting of 36 filaments F with a filamentfineness D of 135 dtex were produced under the conditions shown in Table10 given later, as described for Example 1, except that, as shown inFIG. 15, a block-shaped temperature regulation pipe 37 for controllingthe temperature of the filaments F was installed upstream of thespinning tube 20, to adjust the temperature TH of the temperatureregulation section in the temperature regulation passage 35 a at 250° C.The cross sectional form of the temperature regulation passage 35 a ofthe temperature regulation pipe 37 was rectangular, and the length LH ofthe temperature regulation section as the length of the temperatureregulation pipe 37 in the running direction of the filaments F was 60mm. Ceramic heaters were installed as heating members 36 in the longside direction 37 a of the rectangular temperature regulation passage 35a. The yarn production conditions and the properties of the obtainedyarns in these examples are shown together in Table 10 given later.

In each example, the swing of the running 36 filaments F in thepositions upstream and downstream of the spinning tube 20 was small, anda good spinning state was observed. It was confirmed that the 36filaments F maintained the disposal of the filaments as achievedimmediately after having been discharged from the spinneret 12, in therange from the upstream side of the spinning tube 20 to the outlet ofthe spinning tube 20, and that the filaments F passed through thespinning tube 20 without being converged (without contacting eachother).

The yarn properties of the wound yarns Y were evaluated. Those ofExample 12 with the running air stream velocity Ve set at 4,250 m/minwere 153% in elongation E, 2.2 g/dtex in strength T and 0.95 in yarnirregularity U%. Compared with Example 1, the winding speed was equal,but a yarn having a higher elongation could be obtained.

Those of Example 13 with the running air stream velocity set at 3,200m/min were 140% in elongation E, 2.4 g/dtex in strength T and 0.92 inyarn irregularity U%. Even if the injection flow rate Ef was lowered, ayarn with the same quality as that of Example 1 could be obtained sincethe temperature regulation means 35 was used.

As in Example 12, the temperature Ti of the filaments F in the positionupstream of the spinning tube 20 was measured and found to be 227° C.The temperature Ti in Example 1 was 215° C. as shown in Table 2, andthis value was lower than those of Examples 12 and 13. This means thatif the temperature of the filaments F before they enter the spinningtube 20 is kept at a high temperature, an equivalent elongation E can beobtained even if the running air stream velocity Ve in the spinning tube20 is lowered. Therefore, since the injection flow rate Ef can bedecreased, the yarn production cost can be reduced.

COMPARATIVE EXAMPLE 5

The apparatus used in Comparative Example 5 was the same as theapparatus shown in FIG. 1 used in Comparative Example 1, except that acylindrical air stream forming section 70 consisting of a cylindricalcooling means 55, a funnel-shaped acceleration section 72 and a tube 73shown in FIG. 3 was installed instead of the cooling means 3, in whichthe cooling air 55 a was sent to the tube 73 for generating a parallelstream 73 a in parallel to the running direction of the filaments F inthe tube 73. The cylindrical air stream forming section 70 had thefollowing dimensions: the distance LD from the spinneret 1 to thecylindrical cooling means 55 (spinneret depth) was 25 mm; the length LPof the cylindrical cooling means 55 in the vertical direction (coolingcylinder length) was 300 mm; the angle of the funnel-shaped accelerationsection 74 (acceleration taper angle) was 60°; the length LR of thefunnel-shaped acceleration section in the vertical direction(acceleration length) was 55 mm; the length LN of the tube 73 (tubelength) was 450 mm; and the tube diameter d1 was 25 mm. The apparatuswas the same as that of Comparative Example 1, except the cylindricalair stream forming section 70.

This apparatus was used to produce a polyester yarn consisting of 36filaments F with a filament fineness D of 135 dtex under the conditionsshown in Table 11 given later. The cooling air was supplied to thecylindrical cooling means 55 to achieve a cooling air velocity Vc of 30m/min, and in this case, it was confirmed that the air velocity Vt inthe tube 73 was 2,200 m/min. The yarn production conditions and theproperties of the obtained yarn in Comparative Example 5 are showntogether in Table 11 given later.

The yarn properties of the wound yarn of Comparative Example 5 wereevaluated and found to be 108% in elongation E, 2.9 g/dtex in strength Tand 1.22 in yarn irregularity U%.

The yarn produced in Comparative Example 5 was larger in the value ofyarn irregularity U% than in the examples in conformity with theinvention, though it could be improved in the value of elongation E. Theyarn production apparatus used in Comparative Example 5 was found to belikely to cause yarn irregularity.

Since the yarn was whirled and the filaments F crossed each other at theoutlet of the tube 73, it was confirmed that the filaments F (yarn Y)were disturbed and unstable in running. The reason is that the passagethrough which the filaments F ran had a cylindrical form. Thisphenomenon does not occur in the yarn production method and apparatus ofthe invention, in which the spinning holes of the spinneret are arrangedalong a straight line and in which the cross sectional form of thefilament passage of the spinning tube is rectangular. The cooling airvelocity Vc was raised to raise the air velocity Vt in the tube, but thehigher cooling air velocity Vc caused the discharged numerous filamentsF composed of a polymer to be converged at the center and fused eachother, not being able to be taken up as a yarn Y.

A second group of Examples and Comparative Examples:

The apparatus shown in FIG. 19 was used to produce a polyester yarn forevaluation. The yarn production conditions are shown in Table 12 givenlater. The yarn production state was evaluated for 36 hours after startof yarn production. During this period, the running state of thefilaments F was observed adequately, and the produced yarn was sampledevery 12 hours, for evaluating the yarn properties. The production ofthe yarn was stopped 36 hours after start of production. When theproduction of the yarn was stopped, the state of the filament passage 25in the spinning tube 20 was observed.

The spinning tube 20 used in Example 14 is shown in FIGS. 6 and 7. Thecross sectional form of the filament passage 25 was rectangular. The airinlet section 22 had a widened portion 22 a. The air discharge section24 had a widened portion 24 a. The length Ex of the short sides of therectangle as the cross sectional form of the filament passage 25 in thesteady flow section 21 was 2 mm, and the length Ey of the long sides was100 mm. The injection holes 23 a open on the wall faces of the filamentpassage 25 were formed as slits. The slits were open over the entirelength of the long sides 21L of the rectangle as the cross sectionalform of the filament passage 25. The slit width Ei (see FIG. 9) of theslits was 0.4 mm.

For the suction gas velocity SV occurring at each gas suction port 62 ofthe gas suction device 60, the correlation between the values indicatedby the pressure gauge 67 and the achieved gas velocities was measuredbeforehand, to obtain the value of the suction gas velocity SV. Thenumerous filaments F were guided to run downward at the center betweenthe gas suction ports 62 installed on both sides of the filaments. Thedistance between each gas suction port 62 and the filaments F (suctiondistance PL) was set at ½ of the distance between both the gas suctionports 62.

For the suction spaces 80 provided between the gas suction device 60 andthe spinning tube 20 as shown in FIG. 23, honeycomb grate members(thickness 15 mm, grate pitch 3 mm) were used and installed on bothsides of the numerous filaments F in parallel with them. Like the gassuction device 60, side plates 68 were used to close the faces in theshort side direction against the outside (see FIG. 22).

In FIG. 19, SL (mm) indicates the distance from the bottom face of thespinneret 12 to the top face of the gas suction device 60, and definesthe space below the nozzle. BL (mm) indicates the length of the gassuction device 60 in the vertical direction, and defines the suctionregion. AL (mm) indicates the length of the suction spaces 80 (see FIG.23) from the bottom face of the gas suction device 60 to the top face ofthe spinning tube 20 in the vertical direction, and defines theventilation distance.

In FIG. 18, L1 (mm) indicates the distance from the bottom face of thespinneret 12 to the top face of the spinning tube 20, and defines thespinning tube position. L2 (mm) indicates the overall length of thespinning tube 20 and defines the spinning tube length. L3 (mm) indicatesthe distance from the bottom face of the spinneret 12 to the oilingmeans 17 and defines the oiling position. L4 (mm) indicates the distancefrom the bottom face of the spinneret to the first godet roller 14, anddefines the take-up position. Vw (m/min) indicates the yarn Y take-upspeed by the first godet roller 14, and defines the take-up speed. InFIG. 6, Es (mm) indicates the distance from the top face of the spinningtube 20 to the injection holes 23 a of the air injection section 23 (thecenter of the open faces of the injection holes 23 a in the verticaldirection on the wall faces of the filament passage 25), and defines theslit position.

For the spinneret 12, the distance between the respectively adjacentspinning holes 13 is called the spinning hole pitch P (mm), and the holediameter of the spinning holes 13 on the bottom face of the spinneret 12is called the spinning hole diameter d (mm). The center distance betweenthe two spinning holes most apart from each other among the pluralspinning holes 13 is called the distance dw (mm) between the outermostspinning holes.

EXAMPLE 14

The apparatus of FIG. 19 was used to produce a polyester yarn (PET yarn)consisting of 36 filaments F with a filament fineness D of 135 dtexunder the conditions shown in Table 12 given later at a speed of 5,000m/min. The spinneret 12 used had all the numerous spinning holesarranged in a straight line Z as shown in FIG. 5A. The spinning holepitch P was 2.5 mm, the spinning hole diameter d was 0.3 mm, and thedistance dw between the outermost spinning holes was 87.5 mm.

EXAMPLE 15 AND COMPARATIVE EXAMPLE 6

Example 15 and Comparative Example 6 were carried out under the sameconditions, except that the gas suction velocity SV was changed. Theyarn properties of the yarns sampled after lapse of predetermined timesare shown in Table 13. The evaluated yarn properties were strength T,elongation E, yarn irregularity U% and fluff K. Table 13 also shows theresults of the inner face of the filament passage 25 of the spinningtube 20 observed 36 hours after start of yarn production.

To measure the strength T and elongation E, a test yarn with a length of50 mm cut from a produced yarn (multifilament) was stretched at atensile speed of 400 mm/min till it was broken using a general tensiletester. To measure the yarn irregularity U%, Uster Tester 1 Model Cproduced by Zellweger Co., Ltd. was used, and a yarn was supplied at aspeed of 100 m/min for measuring in the normal mode. To measure thefluff K, a fly counter produced by Toray Engineering Co., Ltd. was usedto count the number of fluffy pieces in a measuring length of 12,000 mat a speed of 400 m/min.

In each of Example 14 and 15, the swing of filaments F was smallthroughout the yarn production period, and a good spinning state wasmaintained. It was confirmed that the numerous filaments F maintainedthe disposal of the filaments as achieved immediately after having beendischarged from the spinneret 12, in the range from the spinneret 12 tothe outlet of the spinning tube 20, and that the filaments passedthrough the spinning tube 20 without being converged (without contactingeach other). The yarn properties of the wound yarns were evaluated. Asshown in Table 13, the yarn irregularity U% values in Example 14 were0.85 after lapse of 12 hours, 0.88 after lapse of 24 hours and 0.84after lapse of 36 hours, and those in Example 15 were 0.83 after lapseof 12 hours, 0.80 after lapse of 24 hours and 0.82 after lapse of 36hours. On the whole, the fluff of yarns was not observed. Thirty sixhours after start of yarn production, the yarn production was stopped,and the spinning tube 20 was dismantled, to inspect the deposition ofthe volatile matter onto the filament passage 25. The deposition of thevolatile substance was substantially not observed, and the filamentpassage was little contaminated and kept in a good state.

On the other hand, in Comparative Example 6 in which the gas suctiondevice 60 was not used for suction, the filaments F entering thespinning tube 20 began to swing after lapse of about 18 hours, and itwas observed that the swing became large after lapse of about 30 hours.The yarn irregularity U% of the obtained yarn became worse with thelapse of time. Though no fluff existed in the yarn sampled immediatelyafter start of yarn production, the fluff of the sampled yarn increasedwith the lapse of time. After lapse of 36 hours, the filament passage 25of the spinning tube 20 was observed, and it was found that a largeamount of a deposit like white powder had been deposited, and that theair injection section 23 had been partially clogged. The deposit wasexamined by means of chromatography, and it was confirmed that the maincomponent was hydroxyethyl terephthalate sublimed from the polyester.

The examples used polyethylene terephthalate yarns (PET yarns) onlysince they are typical polyester yarns, but in the invention, thepolymer used is not especially limited. For example, also in theproduction of yarns of polyamide, polypropylene and aliphatic polyesters(polylactic acid, etc.), similar effects can be obtained. The yarnproduction method and apparatus can be especially preferably applied toa polylactic acid yarn, since it generates a large amount of a volatilematter. TABLE 1 Item Unit Example 1 Example 2 Example 3 Example 4 Vw:Take-up speed m/min 5,000 ″ ″ ″ D: Fineness dtex 135 ″ ″ ″ F: Number offilaments Number 36 ″ ″ ″ d: Spinning hole diameter mm 0.3 ″ ″ ″ P:Spinning hole pitch mm 2.5 ″ ″ ″ L2: Spinning tube length mm 300 ″ ″ ″Ey: Length of long sides of passage mm 100 ″ ″ ″ Ex: Length of shortsides of passage mm 2 ″ ″ ″ θ: Injection angle degrees 15 ″ ″ ″ Ei:Injection slit width mm 0.4 ″ ″ ″ Es: Injection slit position mm 50 ″ ″″ L1: Spinning tube position mm 100 200 300 400 L3: Oiling meansposition mm 1,500 ″ ″ ″ L4: Take-up position mm 3,200 ″ ″ ″ Ef:Injection flow rate m³/min 0.5 ″ ″ ″ Vs: Injection velocity m/min 6,000″ ″ ″ Ve: Running air stream velocity m/min 4,250 ″ ″ ″ T: Strengthg/dtex 2.4 2.6 2.8 3.0 E: Elongation % 141 128 104 86 U %: Yarnirregularity U value 0.95 0.93 1.00 1.13

TABLE 2 Exam- Exam- Exam- Exam- Item Unit ple 1 ple 2 ple 3 ple 4 Lg:Take-up speed mm 900 900 1,000 1,100 reaching position La: Maximum mm250 350 450 550 acceleration position Ti: Filament temperature ° C. 215203 184 158 VL: Filament speed at m/min 1,800 2,200 2,400 2,500 maximumacceleration position Le: Spinning tube range L1: mm 100 200 300 400L1 + L2 mm 400 500 600 700

TABLE 3 Com- Com- Com- parative parative parative Item Unit Example 1Example 2 Example 3 Vw: Take-up speed m/min 5,000 4,000 3,500 D:Fineness dtex 135 ″ ″ F: Number of filaments Number 36 ″ ″ d: Spinninghole diameter mm 0.3 ″ ″ L22: Cooling length mm 1,000 ″ ″ EY: Coolingsection width mm 200 ″ ″ L11: Cooling means mm 80 ″ ″ position L33:Oiling means position mm 1,500 ″ ″ L44: Take-up position mm 3,200 ″ ″Vcl: Cooling air velocity m/min 30 ″ ″ T: Strength g/dtex 3.1 2.9 2.7 E:Elongation % 65 98 119 U %: Yarn irregularity U value 1.24 1.13 1.05

TABLE 4 Comparative Comparative Comparative Item Unit Example 1 Example2 Example 3 Lg: Take-up speed mm 700 900 800 reaching position La:Maximum mm 650 550 450 acceleration position

TABLE 5 Com- parative Item Unit Example 1 Example 5 Example 4 Vw:Take-up speed m/min 5,000 ″ ″ D: Fineness dtex 135 ″ ″ F: Number offilaments Number 36 ″ ″ d: Spinning hole diameter mm 0.3 ″ ″ P: Spinninghole pitch mm 2.5 ″ ″ L2: Spinning tube length mm 300 ″ ″ Ey: Length oflong sides mm 100 ″ ″ of passage Ex: Length of short sides mm 2 ″ ″ ofpassage θ: Injection angle degrees 15 ″ ″ Ei: Injection slit width mm0.4 ″ ″ Es: Injection slit position mm 50 ″ ″ L1: Spinning tube positionmm 100 ″ ″ L3: Oiling means position mm 1,500 ″ ″ L4: Take-up positionmm 3,200 ″ ″ Ef: Injection flow rate m³/min 0.5 0.4 0.3 Vs: Injectionvelocity m/min 6,000 4,900 3,400 Ve: Running air stream m/min 4,2503,240 1,980 velocity T: Strength g/dtex 2.4 3.2 3.5 E: Elongation % 141112 84 U %: Yarn irregularity U value 0.95 1.01 1.34

TABLE 6 Comparative Item Unit Example 1 Example 5 Example 4 Lg: Take-upspeed mm 900 1,000 1,000 reaching position La: Maximum mm 250 350 650acceleration position VL: Filament speed m/min 1,800 2,300 3,500 atmaximum acceleration position Le: Spinning tube range L1: mm 100 100 100L1 + L2 mm 400 400 400

TABLE 7 Item Unit Example 1 Example 6 Example 7 Vw: Take-up speed m/min5,000 ″ ″ D: Fineness dtex 135 ″ ″ F: Number of filaments Number 36 ″ ″d: Spinning hole diameter mm 0.3 ″ ″ P: Spinning hole pitch mm 2.5 ″ ″L2: Spinning tube length mm 300 900 900 Ey: Length of long sides mm 100″ ″ of passage Ex: Length of short sides mm 2 ″ ″ of passage θ:Injection angle degrees 15 ″ ″ Ei: Injection slit width mm 0.4 ″ ″ Es:Injection slit position mm 50 ″ ″ L1: Spinning tube position mm 100 ″ ″L3: Oiling means position mm 1,500 ″ ″ L4: Take-up position mm 3,200 ″ ″Ef: Injection flow rate m³/min 0.5 ″ 0.6 Vs: Injection velocity m/min6,000 ″ 6,600 Ve: Running air stream m/min 4,250 3,680 4,200 velocity T:Strength g/dtex 2.4 2.7 2.4 E: Elongation % 141 128 140 U %: Yarnirregularity U value 0.95 0.80 0.82

TABLE 8 Example Item Unit Example 1 Example 8 Example 9 10 Vw: Take-upspeed m/min 5,000 ″ ″ ″ D: Fineness dtex 135 ″ ″ ″ F: Number offilaments Number 36 ″ ″ ″ d: Spinning hole diameter mm 0.3 ″ ″ ″ P:Spinning hole pitch mm 2.5 ″ ″ ″ W: Spinning hole row pitch mm — 2.5 2.52.5 L2: Spinning tube length mm 300 ″ ″ ″ Ey: Length of long sides ofpassage mm 100 50 50 50 Ex: Length of short sides of passage mm 2 ″ ″ ″θ: Injection angle degrees 15 ″ 10 5 Ei: Injection slit width mm 0.4 ″ ″″ Es: Injection slit position mm 50 ″ ″ ″ L1: Spinning tube position mm100 ″ ″ ″ L3: Oiling means position mm 1,500 ″ ″ ″ L4: Take-up positionmm 3,200 ″ ″ ″ Ef: Injection flow rate m³/min 0.5 0.25 0.25 0.25 Vs:Injection velocity m/min 6,000 5,900 5,900 5,900 Ve: Running air streamvelocity m/min 4,250 4,190 4,780 5,230 T: Strength g/dtex 2.4 2.4 2.42.3 E: Elongation % 141 140 143 145 U %: Yarn irregularity U value 0.950.98 0.91 0.88

TABLE 9 Item Unit Example 1 Example 11 Vw: Take-up speed m/min 5,000 ″D: Fineness dtex 135 ″ F: Number of filaments Number 36 ″ d: Spinninghole diameter mm 0.3 ″ P: Spinning hole pitch mm 2.5 ″ Lc: Airregulation plate length mm — 60 Lt: Air regulation plate thickness mm —10 L2: Spinning tube length mm 300 ″ Ey: Length of long sides mm 100 ″of passage Ex: Length of short sides mm 2 ″ of passage θ: Injectionangle degrees 15 ″ Ei: Injection slit width mm 0.4 ″ Es: Injection slitposition mm 50 ″ L1: Spinning tube position mm 100 ″ L3: Oiling meansposition mm 1,500 ″ L4: Take-up position mm 3,200 ″ Ef: Injection flowrate m³/min 0.5 ″ Vs: Injection velocity m/min 6,000 ″ Ve: Running airstream m/min 4,250 ″ velocity T: Strength g/dtex 2.4 2.4 E: Elongation %141 143 U %: Yarn irregularity U value 0.95 0.85

TABLE 10 Example Example Item Unit Example 1 12 13 Vw: Take-up speedm/min 5,000 ″ ″ D: Fineness dtex 135 ″ ″ F: Number of filaments Number36 ″ ″ d: Spinning hole diameter mm 0.3 ″ ″ P: Spinning hole pitch mm2.5 ″ ″ LH: Temperature mm — 60 60 regulation section length TH:Temperature ° C. — 250 250 regulation section temperature L2: Spinningtube length mm 300 ″ ″ Ey: Length of long sides mm 100 ″ ″ of passageEx: Length of short sides mm 2 ″ ″ of passage θ: Injection angle degrees15 ″ ″ Ei: Injection slit width mm 0.4 ″ ″ Es: Injection slit positionmm 50 ″ ″ L1: Spinning tube position mm 100 ″ ″ L3: Oiling meansposition mm 1,500 ″ ″ L4: Take-up position mm 3,200 ″ ″ Ef: Injectionflow rate m³/min 0.5 ″ 0.4 Vs: Injection velocity m/min 6,000 ″ 4,500Ve: Running air stream m/min 4,250 ″ 3,200 velocity T: Strength g/dtex2.4 2.2 2.4 E: Elongation % 141 153 140 U %: Yarn irregularity U value0.95 0.95 0.92

TABLE 11 Item Unit Comparative Example 5 Vw: Take-up speed m/min 5,000D: Fineness dtex 135 F: Number of filaments Number 36 d: Spinning holediameter mm 0.3 LP: Cooling tube length mm 300 d1: Tube diameter mm 25θ1: Acceleration taper angle degrees 60 Lb: Tube length mm 450 LR:Acceleration length mm 55 L3: Oiling means position mm 1,500 L4: Take-upposition mm 3,200 Vc: Cooling air velocity m/min 30 Vt: Tube airvelocity m/min 2,200 T: Strength g/dtex 2.9 E: Elongation % 108 U %:Yarn irregularity U value 1.22

TABLE 12 Com- Example Example parative Item Unit 14 15 Example 6 Vw:Take-up speed m/min 5,000 ″ ″ D: Fineness dtex 135 ″ ″ F: Number offilaments Number 36 ″ ″ d: Spinning hole diameter mm 0.3 ″ ″ P: Spinninghole pitch mm 2.5 ″ ″ TP: Nozzle temperature ° C. 285 ″ ″ SL: Spacebelow nozzle mm 5 ″ ″ BL: Suction region mm 45 ″ ″ AL: Ventilationdistance mm 50 ″ ″ Sv: Suction gas velocity m/min 10 30 0 PL: Suctiondistance mm 10 ″ ″ L2: Spinning tube length mm 300 ″ ″ Ey: Length oflong sides mm 100 ″ ″ of passage Ex: Length of short sides mm 2 ″ ″ ofpassage θ: Injection angle degrees 15 ″ ″ Ei: Injection slit width mm0.4 ″ ″ Es: Injection slit position mm 50 ″ ″ L1: Spinning tube positionmm 100 ″ ″ L3: Oiling means position mm 1,500 ″ ″ L4: Take-up positionmm 3,200 ″ ″ Vs: Injection velocity m/min 6,000 ″ ″ Ve: Running airstream m/min 4,250 ″ ″ velocity

TABLE 13 Example Example Comparative Item Unit 14 15 Example 6 Afterlapse T: Strength g/dtex 2.5 2.6 2.4 of 12 hours E: Elongation % 135 136130 U %: Yarn irregularity U value 0.85 0.83 1.00 K: Number of fluffpieces Number/12 km 0 0 0 After lapse T: Strength g/dtex 2.5 2.6 2.4 of14 hours E: Elongation % 135 136 130 U %: Yarn irregularity U value 0.880.80 1.10 K: Number of fluff pieces Number/12 km 0 0 18 After lapse T:Strength g/dtex 2.5 2.6 2.4 of 36 hours E: Elongation % 135 136 130 U %:Yarn irregularity U value 0.84 0.82 1.14 K: Number of fluff piecesNumber/12 km 0 0 67 Result of Little Little Much confirmation ofcontamination after lapse of 36 hours

INDUSTRIAL APPLICABILITY

The yarn production method and apparatus of the invention use aspinneret having numerous spinning holes arranged at a desired pitch asa row or plural rows in a straight line(s), a spinning tube (ejector)having a filament passage through which a row(s) of numerous filamentscomposed of a polymer discharged from the spinning holes and runningdownward from the spinneret pass (es), an oiling means for applying anoiling agent to the numerous filaments coming out of the spinning tube,a take-up means for taking up the oiled numerous filaments, and a yarnwinding means for winding the numerous filaments coming from the take-upmeans, wherein in the filament passage of the spinning tube, air isinjected obliquely downward toward the numerous filaments disposed inthe row direction of the spinning holes and entering the filamentpassage, from both sides of the disposal of the numerous filaments, todispose the numerous filaments in one row without allowing them tooverlap each other, and the air stream formed as a confluence of the airstreams injected obliquely downward from both sides and running downwardin the filament passage acts on the disposed numerous filaments runningdownward in the filament passage for drawing them, to make them thinner,before the polymer constituting the filaments is solidified; in thisyarn production process, since the velocity of the air stream runningdownward in the filament passage is not less than 60% of the take-upspeed of the numerous filaments taken up by the take-up means or sincethe gas generated from the numerous filaments is sucked and dischargedoutside in the range between the spinneret and the spinning tube, a yarnwith a high elongation can be wound by a yarn winding means even if theyarn take-up speed of the take-up means is high. The obtained yarn issmall in the irregularity between filaments. Even in the case where thewidth of the filament passage in the direction perpendicular to thedirection in which the numerous filaments are disposed side by side issmall, since the gas generated from the numerous filaments in the rangebetween the spinneret and the spinning tube is sucked and dischargedoutside, it can be prevented that the volatile substance of thefilaments contaminates the filament passage having a narrow width. So, astable yarn can be continuously produced without suspension of yarnproduction.

1. A method for producing a yarn consisting of numerous filaments,using: (a) a spinneret having numerous spinning holes to discharge aflowable polymer continuously for forming filaments, (b) a spinning tubehaving a filament passage through which the numerous filaments formed bysaid numerous spinning holes run downward from said spinneret, andinstalled below and spaced from said spinneret, (c) an oiling means forapplying an oil to the numerous filaments coming out of said spinningtube, (d) a filament take-up means for taking up the numerous filamentscoming from said oiling means, and (e) a winding means for winding thenumerous filaments coming from said filament take-up means,characterized in that (f) gas injection holes are provided, which injectgas obliquely downward from outside the numerous filaments entering thefilament passage of said spinning tube, toward the numerous filaments,while the numerous filaments are still flowable, to ensure that thenumerous filaments can be disposed along one straight line or one circlewithout overlapping each other, and further to ensure that, subsequentlyafter disposing the numerous filaments, the injected gas can form a gasstream flowing downward together with the numerous filaments in thefilament passage of said spinning tube, and (g) the velocity of the gasstream flowing downward together with the numerous filaments in thefilament passage of said spinning tube is not less than 60% of a take-upspeed of the numerous filaments taken up by said filament take-up means.2. A method for producing a yarn, according to claim 1, wherein saidnumerous filaments are disposed along one straight line; the crosssectional form of the filament passage of said spinning tube isrectangular; the direction of the long sides of said rectangle agreeswith the direction of said straight line; and the following relation issatisfiedd×3≦Ex≦d×20 where Ex is the length of the short sides of said rectangle,and d is the diameter of said spinning holes.
 3. A method for producinga yarn, according to claim 2, wherein said numerous spinning holes arearranged in straight lines; and the number of the straight lines is 3 orless.
 4. A method for producing a yarn, according to claim 1, whereinthe following relation is satisfied:La≦Lg/2 where Lg is the distance between said spinneret and the positionat which said numerous filaments are solidified to lose theirflowability and reach the take-up speed of the numerous filaments takenup by said filament take-up means, and La is the distance between saidspinneret and the position at which the acceleration of said numerousfilaments becomes largest.
 5. A method for producing a yarn, accordingto claim 4, wherein the velocity of the gas stream flowing downwardtogether with said numerous filaments in the filament passage of saidspinning tube is higher than the running speed of said numerousfilaments in the range of the distance Lg between said spinneret and theposition at which the running speed of said numerous filaments reachesthe take-up speed of the numerous filaments taken up by said filamenttake-up means.
 6. A method for producing a yarn, according to claim 1,wherein a gas suction and discharge means for sucking and discharginggas existing around the numerous filaments running from said spinningholes toward said filament passage is installed between said spinneretand said spinning tube, to ensure that the gas existing around saidnumerous filaments can be sucked and discharged.
 7. A method forproducing a yarn, according to claim 6, wherein the numerous filamentsare disposed along one straight line; the cross sectional form of thefilament passage of said spinning tube is rectangular; the direction ofthe long sides of said rectangle agrees with the direction of saidstraight line; and the following relation is satisfiedEx≦10 mm where Ex is the length of the short sides of said rectangle. 8.A method for producing a yarn consisting of numerous filaments, using:(a) a spinneret having numerous spinning holes formed to discharge aflowable polymer continuously for forming filaments, (b) a spinning tubehaving a filament passage through which the numerous filaments formed bysaid numerous spinning holes run downward from said spinneret, andinstalled below and spaced from said spinneret, (c) an oiling means forapplying an oil to the numerous filaments coming out of said spinningtube, (d) a filament take-up means for taking up the numerous filamentscoming from said oiling means, and (e) a winding means for winding thenumerous filaments coming from said filament take-up means,characterized in that (f) gas injection holes are provided, which injectgas obliquely downward from outside the numerous filaments entering thefilament passage of said spinning tube, toward the numerous filaments,while the numerous filaments are still flowable, to ensure that thenumerous filaments can be disposed along one straight line or one circlewithout overlapping each other, and further to ensure that, subsequentlyafter disposing the numerous filaments, the injected gas can form a gasstream flowing downward together with the numerous filaments in thefilament passage of said spinning tube, and (g) the following relationis satisfied:La≦Lg/2 where Lg is the distance between said spinneret and the positionat which said numerous filaments are solidified to lose theirflowability and reach the take-up speed of the numerous filaments takenup by said filament take-up means, and La is the distance between saidspinneret and the position at which the acceleration of said numerousfilaments becomes largest.
 9. A method for producing a yarn, accordingto claim 8, wherein the velocity of the gas stream flowing downwardtogether with said numerous filaments in said filament passage is higherthan the running speed of said numerous filaments.
 10. A method forproducing a yarn consisting of numerous filaments, using: (a) aspinneret having numerous spinning holes formed to discharge a flowablepolymer continuously for forming filaments, (b) a spinning tube having afilament passage through which the numerous filaments formed by saidnumerous spinning holes run downward from said spinneret, and installedbelow and spaced from said spinneret, (c) an oiling means for applyingan oil to the numerous filaments coming out of said spinning tube, (d) afilament take-up means for taking up the numerous filaments coming fromsaid oiling means, and (e) a winding means for winding the numerousfilaments coming from said filament take-up means, characterized in that(f) gas injection holes are provided, which inject gas obliquelydownward from outside the numerous filaments entering the filamentpassage of said spinning tube, toward the numerous filaments, while thenumerous filaments are still flowable, to ensure that the numerousfilaments can be disposed along one straight line or one circle withoutoverlapping each other, and further to ensure that, subsequently afterdisposing the numerous filaments, the injected gas can form a gas streamflowing downward together with the numerous filaments in the filamentpassage of said spinning tube, and (g) a gas suction device is providedbetween said spinneret and said spinning tube, to suck the gas existingaround said numerous filaments and to discharge the gas outside.
 11. Amethod for producing a yarn, according to claim 10, wherein the width ofsaid filament passage in the direction perpendicular to the direction inwhich said numerous filaments are disposed side by side is 10 mm orless.
 12. A method for producing a yarn, according to claim 10, whereinthe suction of the gas existing around said numerous filaments iscarried out on both sides of the disposal of said numerous filaments.13. A method for producing a yarn, according to claim 10, wherein saidnumerous spinning holes are arranged in straight lines; and the numberof the straight lines is 3 or less.
 14. A method for producing a yarn,according to claim 10, wherein outside air suction spaces are formedbetween said gas suction device and said spinning tube, to ensure thatthe sucked outside air flows into said filament passage.
 15. Anapparatus for producing a yarn consisting of numerous filaments, having:(a) a spinneret having numerous spinning holes formed to discharge aflowable polymer continuously for forming filaments, (b) a spinning tubehaving a filament passage through which the numerous filaments formed bysaid numerous spinning holes run downward from said spinneret, andinstalled below and spaced from said spinneret, (c) an oiling means forapplying an oil to the numerous filaments coming out of said spinningtube, (d) a filament take-up means for taking up the numerous filamentscoming from said oiling means, and (e) a winding means for winding thenumerous filaments coming from said filament take-up means,characterized in that (f) gas injection holes are provided, which injectgas obliquely downward from outside the numerous filaments entering thefilament passage of said spinning tube, toward the numerous filaments,while the numerous filaments are still flowable, to ensure that thenumerous filaments can be disposed along one straight line or one circlewithout overlapping each other, and further to ensure that, subsequentlyafter disposing the numerous filaments, the injected gas can form a gasstream flowing downward together with the numerous filaments in thefilament passage of said spinning tube, and (g) a means is provided foradjusting the injection conditions of the gas injected from said gasinjection holes or adjusting the take-up speed of the numerous filamentstaken up by said filament take-up means, to ensure that the velocity ofthe gas stream flowing downward together with the numerous filaments inthe filament passage of said spinning tube is not less than 60% of thetake-up speed of the numerous filaments taken up by said filamenttake-up means.
 16. An apparatus for producing a yarn, according to claim15, wherein said numerous filaments are disposed along one straightline; the cross sectional form of the filament passage of said spinningtube is rectangular; the direction of the long sides of said rectangleagrees with the direction of said straight line; and the followingrelation is satisfied:d×3≦Ex≦d×20 where Ex is the length of the short sides of said rectangle,and d is the diameter of said spinning holes.
 17. An apparatus forproducing a yarn, according to claim 16, wherein said numerous spinningholes are arranged in straight lines; and the number of the straightlines is 3 or less.
 18. An apparatus for producing a yarn, according toclaim 15, wherein the following relation is satisfied:La≦Lg/2 where Lg is the-distance between said spinneret and the positionat which said numerous filaments are solidified to lose theirflowability and reach the take-up speed of the numerous filaments takenup by said filament take-up means, and La is the distance between saidspinneret and the position at which the acceleration of said numerousfilaments becomes largest.
 19. An apparatus for producing a yarn,according to claim 18, wherein the velocity of the gas stream flowingdownward together with said numerous filaments in the filament passageof said spinning tube is higher than the running speed of said numerousfilaments, in the range of the distance Lg between said spinneret andthe position at which the running speed of the numerous filamentsreaches the take-up speed of the numerous filaments taken up by saidfilament take-up means.
 20. An apparatus for producing a yarn, accordingto claim 15, wherein a gas suction and discharge means for sucking anddischarging the gas existing around the numerous filaments running fromsaid spinning holes toward said filament passage is installed betweensaid spinneret and said spinning tube, to ensure that the gas existingaround said numerous filaments can be sucked and discharged.
 21. Anapparatus for producing a yarn, according to claim 20, wherein thenumerous filaments are disposed along one straight line; the crosssectional form of the filament passage of said spinning tube isrectangular; the direction of the long sides of said rectangle agreeswith the direction of said straight line; and the following relation issatisfied:Ex≦10 mm where Ex is the length of the short sides of said rectangle.22. An apparatus for producing a yarn consisting of numerous filaments,having: (a) a spinneret having numerous spinning holes formed todischarge a flowable polymer continuously for forming filaments, (b) aspinning tube having a filament passage through which the numerousfilaments formed by said numerous spinning holes run downward from saidspinneret, and installed below and spaced from said spinneret, (c) anoiling means for applying an oil to the numerous filaments coming out ofsaid spinning tube, (d) a filament take-up means for taking up thenumerous filaments coming from said oiling means, and (e) a windingmeans for winding the numerous filaments coming from said filamenttake-up means, characterized in that (f) gas injection holes areprovided, which inject gas obliquely downward from outside the numerousfilaments entering the filament passage of said spinning tube, towardthe numerous filaments, while the numerous filaments are still flowable,to ensure that the numerous filaments can be disposed along one straightline or one circle without overlapping each other, and further to ensurethat, subsequently after disposing the numerous filaments, the injectedgas can form a gas stream flowing downward together with the numerousfilaments in the filament passage of said spinning tube, and (g) thefollowing relation is satisfied:La≦Lg/2 where Lg is the distance between said spinneret and the positionat which said numerous filaments are solidified to lose theirflowability and reach the take-up speed of the numerous filaments takenup by said filament take-up means, and La is the distance between saidspinneret and the position at which the acceleration of said numerousfilaments becomes largest.
 23. An apparatus for producing a yarn,according to claim 22, wherein the velocity of the gas stream flowingdownward together with said numerous filaments in said filament passageis higher than the running speed of said numerous filaments.
 24. Anapparatus for producing a yarn consisting of numerous filaments, having:(a) a spinneret having numerous spinning holes formed to discharge aflowable polymer continuously for forming filaments, (b) a spinning tubehaving a filament passage through which the numerous filaments formed bysaid numerous spinning holes run downward from said spinneret, andinstalled below and spaced from said spinneret, (c) an oiling means forapplying an oil to the numerous filaments coming out of said spinningtube, (d) a filament take-up means for taking up the numerous filamentscoming from said oiling means, and (e) a winding means for winding thenumerous filaments coming from said filament take-up means,characterized in that (f) gas injection holes are provided, which injectgas obliquely downward from outside the numerous filaments entering thefilament passage of said spinning tube, toward the numerous filaments,while the numerous filaments are still flowable, to ensure that thenumerous filaments can be disposed along one straight line or one circlewithout overlapping each other, and further to ensure that, subsequentlyafter disposing the numerous filaments, the injected gas can form a gasstream flowing downward together with the numerous filaments in thefilament passage of said spinning tube, and (g) a gas suction device isinstalled between said spinneret and said spinning tube, to suck the gasexisting around said numerous filaments and to discharge the gasoutside.
 25. An apparatus for producing a yarn, according to claim 24,wherein the width of said filament passage in the directionperpendicular to the direction in which said numerous filaments aredisposed side by side is 10 mm or less.
 26. An apparatus for producing ayarn, according to claim 24, wherein the suction of the gas existingaround said numerous filaments is carried out on both sides of thedisposal of said numerous filaments.
 27. An apparatus for producing ayarn, according to claim 24, wherein said numerous spinning holes arearranged in straight lines; and the number of the straight lines is 3 orless.
 28. An apparatus for producing a yarn, according to claim 24,wherein outside air suction spaces are formed between said gas suctiondevice and said spinning tube, to ensure that the sucked outside airflows into said filament passage.